Sanjana T. answered • 06/01/22
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To solve by substitution is to replace a variable with an expression or term that makes all the variables in the equation you are trying to solve the same.
Step 1: first we have to solve for a variable. In this case we already have x= 2y - 4, so we don’t need to solve for anything since they gave it to us nicely solved.
Step 2: Next, replace x in equation 1 for the expression from equation 2. Everywhere the first equation has an x, we can replace it with 2y - 4 since we know that is what x equals to. This leaves us with
(2y - 4) + 8y = 16
Step 3: Let’s solve the new equation and find the value of y
2y - 4 + 8y = 16
10y - 4 = 16
y = 2
Step 4: use the value of y to find value of x. We can use the original equation x = 2y - 4 to find x
x = 2(2) - 4
x = 0
Our answer is wanted in coordinate form (x,y), which will be written as (0,2)
