Question

1. which expression can be substituted for y in the top equation of the system to solve the system by substitution?

$4x + 3y = 9$
$3x + y = 8$
$3x - 8$
$\frac{3}{4}y + 3$
$-3x + 8$
$12x - 3y$

Explanation:

Step1: Isolate y in bottom equation

Start with $3x + y = 8$. Subtract $3x$ from both sides:
$y = 8 - 3x$ or $y = -3x + 8$

Answer:

-3x + 8