Maths-
General
Easy

Question

x2 + 10 = 91
What is the positive solution to the given equation?

  1. 9  
  2. 10  
  3. 41  
  4. 51  

The correct answer is: 9


    HINT: Rearrange the equation and perform factorization.
    Complete step by step Solution
    Given the equation is x to the power of 2 end exponent blank plus blank 10 blank equals blank 91.
    On subtracting 91 from both the sides, we get,
    x to the power of 2 blank end exponent plus blank 10 blank minus 91 blank equals blank 91 blank equals blank 91
    Thus, we get, x to the power of 2 end exponent blank minus blank 81 blank equals blank 0
    By applying the algebraic identity, a to the power of 2 end exponent blank minus blank b to the power of 2 end exponent blank equals blank left parenthesis a blank plus blank b right parenthesis left parenthesis a blank minus blank b right parenthesis to the LHS
    we get,
    Then, either or x = - 9 or x = 9.
    On solving these equations, x can take the values -9 or 9.
    Since we are asked to find the positive value of the equation, the value of x will be 9.
    Note: We can find the solution also by knowing the square root of 81 here. That is, we will have the equation to be x2 = 81. By taking square roots on both sides, we will end up with values 9 and -9. From this, we will choose only the positive value that is 9 here.

    Related Questions to study

    General
    Maths-

    x squared minus 12 x plus 23 equals 0
    Which of the following is a solution to the given equation?

    x squared minus 12 x plus 23 equals 0
    Which of the following is a solution to the given equation?

    Maths-General
    General
    Maths-


    The graph of the function f defined by f left parenthesis x right parenthesis equals 1 fourth left parenthesis x plus 4 right parenthesis squared minus 5 is shown. The graph passes through the points left parenthesis negative 10 comma a right parenthesis text  and  end text left parenthesis a comma b right parenthesis comma where a and b are constants. What is the value of b ?


    The graph of the function f defined by f left parenthesis x right parenthesis equals 1 fourth left parenthesis x plus 4 right parenthesis squared minus 5 is shown. The graph passes through the points left parenthesis negative 10 comma a right parenthesis text  and  end text left parenthesis a comma b right parenthesis comma where a and b are constants. What is the value of b ?

    Maths-General
    General
    Maths-

    5 x minus 2 plus 3 x equals 3 left parenthesis x plus 4 right parenthesis plus 5 x minus 10
    Which of the following statements is true about the equation above?

    5 x minus 2 plus 3 x equals 3 left parenthesis x plus 4 right parenthesis plus 5 x minus 10
    Which of the following statements is true about the equation above?

    Maths-General
    parallel
    General
    Maths-

    y equals left parenthesis x plus 5 right parenthesis squared minus 8
    The equation above can be represented by a parabola in the -plane. The parabola is then translated so that the vertex is at (0, 0). Which of the following best describes the translation?

    y equals left parenthesis x plus 5 right parenthesis squared minus 8
    The equation above can be represented by a parabola in the -plane. The parabola is then translated so that the vertex is at (0, 0). Which of the following best describes the translation?

    Maths-General
    General
    Maths-

    vertical line x plus 2 vertical line equals vertical line x minus 8 vertical line
    What is the solution to the given equation?

    vertical line x plus 2 vertical line equals vertical line x minus 8 vertical line
    What is the solution to the given equation?

    Maths-General
    General
    Maths-


    What is an equation of the graph shown?


    What is an equation of the graph shown?

    Maths-General
    parallel
    General
    Maths-

    Which expression is equivalent to g to the power of 4 over 5 end exponent h to the power of 2 over 5 end exponent, where g and h are positive?

    Which expression is equivalent to g to the power of 4 over 5 end exponent h to the power of 2 over 5 end exponent, where g and h are positive?

    Maths-General
    General
    Maths-

    Which expression is equivalent to x to the power of 4 minus 18 x squared plus 81 ?

    Which expression is equivalent to x to the power of 4 minus 18 x squared plus 81 ?

    Maths-General
    General
    Maths-


    Triangle DEF (not shown) is similar to triangle ABC above, where side DE corresponds to side AB, side DF corresponds to side AC , and DE = AB. What is the measure of angle DEF ?


    Triangle DEF (not shown) is similar to triangle ABC above, where side DE corresponds to side AB, side DF corresponds to side AC , and DE = AB. What is the measure of angle DEF ?

    Maths-General
    parallel
    General
    Maths-


    The function f models Jack's pulse, in beats per minute (bpm), as a function of his speed, in kilometers per hour (km/h), on a stationary bicycle. Based on the model, what was Jack's pulse, in bpm, when his sped was 0 km/h?


    The function f models Jack's pulse, in beats per minute (bpm), as a function of his speed, in kilometers per hour (km/h), on a stationary bicycle. Based on the model, what was Jack's pulse, in bpm, when his sped was 0 km/h?

    Maths-General
    General
    Maths-

    ka + nb = 10
    The given equation relates the positive numbers a, b, k and n. Which of the following correctly expresses a in terms of b, k , and n ?

    ka + nb = 10
    The given equation relates the positive numbers a, b, k and n. Which of the following correctly expresses a in terms of b, k , and n ?

    Maths-General
    General
    Maths-


    What system of linear equations is represented by the lines shown?


    What system of linear equations is represented by the lines shown?

    Maths-General
    parallel
    General
    Maths-

    What is the x-intercept of the graph of 8x + 6y = 24 in the xy-plane?

    What is the x-intercept of the graph of 8x + 6y = 24 in the xy-plane?

    Maths-General
    General
    Maths-

    A college mathematics department plans to spend straight $1,800 buying computers and books. Each computer costs straight $300 and each book costs straight $90 . Which equation represents this situation, where x is the number of computers and y is the number of books that the department can buy?

    A college mathematics department plans to spend straight $1,800 buying computers and books. Each computer costs straight $300 and each book costs straight $90 . Which equation represents this situation, where x is the number of computers and y is the number of books that the department can buy?

    Maths-General
    General
    Maths-

    Which of the following is equivalent to 2 open parentheses x squared minus x close parentheses plus 3 open parentheses x squared minus x close parentheses?

    Which of the following is equivalent to 2 open parentheses x squared minus x close parentheses plus 3 open parentheses x squared minus x close parentheses?

    Maths-General
    parallel

    card img

    With Turito Academy.

    card img

    With Turito Foundation.

    card img

    Get an Expert Advice From Turito.

    Turito Academy

    card img

    With Turito Academy.

    Test Prep

    card img

    With Turito Foundation.