Solve the system by substitution.

y = 3x + 28

y=-4x

Step-by-step explanation:

Substituting y = - 4x then putting in the equation

-4x = 3x + 28

Bringing like terms on one side

-4x - 3x = 28

-7x = 28

- (7x = - 28

x = - 28 / 7 = - 4

(-4, 16)

Step-by-step explanation:

Since y = - 4x, substitute - 4x for y in the first equation:

-4x = 3x + 28, or

-7x = 28. Then x must be - 4.

According to the second equation, y = - 4x. Thus, if x = - 4, y = - 4 (-4) = + 16.

The solution is (-4, 16).