3. solve the system of equations by substitution.

x= -4y
x+5y=2

a. (-8,2)
b. (8,-2)
c. (2/9,-8/9)
d. (-12,3)

4. solve the system of equations by elimination.

3x+4y=31
2x-4y=-6

a. (4,5)
b. (5,4)
c. (-5,12.5)
d. (5,-4)

3. plug in x=-4y to the second one (x+5y=2), we have: -4y+5y=2 => y=2. Then plug y=2 to x=-4y we have x=-4(-2)=8. So the answer will be A: (8,-2)

4. For this one, you add the first equation to the second one, 3x plus 2x = 5x, 4x plus -4x = 0, 31 plus -6= 25. Then we get the final equation is : 5x=25, solve for x we get x=5, plug x=5 to any equation, we get y= 4. So the answer will be B (5,4)