Maths-
General
Easy
Question
x2 + 10 = 91
What is the positive solution to the given equation?
- 9
- 10
- 41
- 51
The correct answer is: 9
HINT: Rearrange the equation and perform factorization.
Complete step by step Solution
Given the equation is .
On subtracting 91 from both the sides, we get,
Thus, we get,
By applying the algebraic identity, 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.
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