Practice Substitution in Math
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
Replacing every occurrence of a variable or sub-expression with an equivalent value or expression throughout a problem.
If y = 2x, you can write 2x everywhere you see y—they're the same.
Example 1
easyIf y = 3x + 1 and x = 2, find y.
Example 2
mediumIf y = x + 3 and 2x + y = 9, use substitution to solve for x.
Example 3
easyEvaluate a + 2b when a = 5 and b = -1.
Example 4
mediumIf u = 2v - 1 and 3u + v = 11, find v.