waecmaths question:
Solve for y in the equations
$2x-3y=22$
$3x+2y=7$
Option A:
–5
Option B:
–4
Option C:
4
Option D:
5
waecmaths solution:
$\begin{align} & 2x-3y=22---(i) \\ & 3x+2y=7---(ii) \\ & \text{Multiply }(i)\text{ by }2 \\ & 4x-6y=44---(iii) \\ & \text{Multiply }(ii)\text{ by }3 \\ & 9x+6y=21---(iv) \\ & \text{Add (iii) and (iv) together} \\ & 13x=65 \\ & x=5 \\ & \text{Substitude }x=5\text{ into }(i) \\ & 2(5)-3y=22 \\ & 10-3y=22 \\ & -3y=12 \\ & y=-4 \\\end{align}$
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