Answer: (-3,-12)
Step-by-step explanation:
Step 1: Solve Y = 4x
Step 2: Substitute 4x for y in 3x + y = -21
3x + y =-21
3x + 4x = -21
7x = -21( Divide both sides by 7)
7x/7 = -21/7
X = -3
Step 3: Substitute -3 for X in Y = 4x
Y = 4x
Y = (4)(-3)
Y= -12
