16Hit1600
AlgebraHardZero of a linear function from slope and intercept

Algebra practice question

The linear function f has a slope of −2, and f(0) = 8. For what value of x is f(x) = 0?

Answer: 4

f(x) = −2x + 8. Set −2x + 8 = 0: 2x = 8, x = 4.

Common wrong answers

If you answered 8
8 is f(0), the y-intercept, not the zero.
If you answered 16
16 is 8 × 2, multiplying by the slope's size instead of dividing.
If you answered -4
−4 has the wrong sign: −2x = −8 gives x = 4.

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