# Unit 2 logic and proof homework 6 algebraic proof

### Question:

What is the substitution rule?

### Answer:

If a=b, then in any equation or expression, a can be changed to b. This is known as the substitution property of equality. “If a variable x is equal to another variable y, then x can be used in place of y in any equation or expression, and y can be used in place of x in any equation or expression,” says the substitution property of equality. You can figure out the value of an expression by replacing letters with numbers. The method of substitution is mostly made up of three steps: Find the answer for the variable in one of the equations. Add this expression to the other equation, and then figure out the answer. Backtrack to the original equation and plug in the value to find the variable that goes with it.