Question

Given two equations :
$3x–4y=1$ ---------- (1)
$5x–6y=7$ ---------- (2)
What has to be done so that the coefficients of $x$ are equal?

• A. Multiply equation (1) by 6 and equation (2) by 4.
• B. Multiply equation (1) by 3 and equation (2) by 5.
• C. Multiply equation (1) by 5 and equation (2) by 3.
• D. None of the above

Answer 1

The correct option is C Multiply equation (1) by 5 and equation (2) by 3.

Coefficient of $x$ in equation (1) is 3.
Coefficient of $x$ in equation (2) is 5.
So, to make coefficients of $x$ equal, multiply equation (1) by 5 and equation (2) by 3.
$\text{Equation}\left(1\right)\times 5\Rightarrow 15x–20y=5$
$\text{Equation (2)}\times 3\Rightarrow 15x–18y=21$