AlgebraMediumWhere two linear functions are equal
Algebra practice question
The functions f and g are defined by f(x) = 2x + 3 and g(x) = 5x − 6. For what value of x is f(x) = g(x)?
Answer: 3
Set 2x + 3 = 5x − 6: 9 = 3x, so x = 3. Both functions equal 9 there.
Common wrong answers
- If you answered 1
- 1 comes from 3 = 3x with the constants mishandled; 3 + 6 = 9.
- If you answered 9
- 9 is the shared VALUE f(3) = g(3), not the input x.
- If you answered -1
- −1 comes from 2x + 3 = 5x − 6 solved as −3 = 3x, subtracting 6 instead of adding.
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