To use the substitution method in order to solve the system of equations, y=7x+8 y=x+20 , first notice that both equations are set equal to the same value, y.
Knowing this, 7x+8 and x+20 both equal the same value so you would set them equal to one another: 7x+8=x+20.
This would be substitution as you are substituting one of the equations in place of y.
Now, solve for x: 7x+8=x+20 6x+8=20 6x=12 x=2
Now that you know x equals the value of 2, you can substitute the value into one of the equations to find y: y=x+20 y=2+20 y=22
Now that you have x=2 and y=22, you can conclude that your answer would be (2,22) or choice B.
