Well basically you are plugging in variables. Lets use a random but simple system of equations. y = 2x - 3 6x + 8y = 20 Now you need to plug in the top equation, which equals y, into the bottom equation. 6x + 8(2x - 3) = 20 6x + 16x - 24 = 20 Combine like terms. 22x - 24 = 20 Add 24 to both sides. 22x = 44 Divide. x = 2 Now plug in 2 in any of the original equations. y = 2x - 3 y = 2(2) - 3 y = 4 - 3 y = 1 So your solution is (2,1). And thats how you use substitution. I hope this helps love! :)
