Question
4x + y = 7
2x - 7y = 1
If(x, y) is the solution to the given system of equations, what is the value of x ?
The correct answer is: 1.6
HINT: Given 2 linear equations with two variables. Solve and find x.
Complete step by step solution:
Let 4x + y = 7…(i) and 2x - 7y = 1…(ii)
Multiply (i) with 7 to make the coefficients of to be the same.
We get (i) to be 7(4x + y = 7) = 28x + 7y = 49
Let 28x + 7y = 49…(iii)
On adding (ii) and (iii)
Then, LHS becomes 2x - 7y + 28x + 7y = 30x
RHS will be 1 + 49 = 50
On equating LHS and RHS, we get 30x = 50
On dividing both sides by 30 we get
Thus, the value of x is = 1.6 .
Note: We can solve this by first multiplying (ii) with 2. We get (ii) to be 4x - 14y = 2 and let this be (iii). By solving (ii) and (iii), we get the value of y to be . By substituting the value of y in (i) we can find the value of x. Thus, we get the value of x to be .
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