Question

solve the system by substitution.
y = -2x - 3
7x + 4y = -7
the solution is (\square, \square ).

Explanation:

Step1: Substitute \( y = -2x - 3 \) into \( 7x + 4y = -7 \)

We replace \( y \) in the second equation with \( -2x - 3 \). So the equation becomes \( 7x + 4(-2x - 3) = -7 \).

Step2: Simplify and solve for \( x \)

First, expand the left - hand side: \( 7x-8x - 12=-7 \). Then combine like terms: \( -x-12 = -7 \). Add 12 to both sides: \( -x=-7 + 12=5 \). Multiply both sides by - 1: \( x=-5 \).

Step3: Substitute \( x = - 5 \) into \( y=-2x - 3 \)

We get \( y=-2\times(-5)-3=10 - 3 = 7 \).

Answer:

\((-5,7)\)