Question

1. $-4x + 5y = -15$ $x + 7y = 12$

Explanation:

Step1: Isolate $x$ from second equation

$x = 12 - 7y$

Step2: Substitute $x$ into first equation

$-4(12 - 7y) + 5y = -15$

Step3: Expand and simplify left side

$-48 + 28y + 5y = -15$
$-48 + 33y = -15$

Step4: Solve for $y$

$33y = -15 + 48$
$33y = 33$
$y = 1$

Step5: Substitute $y=1$ into $x=12-7y$

$x = 12 - 7(1)$
$x = 5$

Answer:

$x=5$, $y=1$