Question

If f(x) is a continuous function defined for all real numbers, f(–10) = –2, f(–8) = 5, and f(x) = 0 for one and only one value of x, then which of the following could be that x value?

a) -7 b) -9 c) 0 d) 2

Answer 1

b: -9

Explanation:

just took the test and got it right :)

Answer 2

B

Explanation:

At x = -10 the function has a value of -2 (negative)

At x = -8, the function has a value of 5 (positive)

So that means the function, when graphed, would have to cross the x-axis between x = -10 and x = -8 for it go from Negative to Positive (jump). That value would be between -10 and -8.

From the answer choices, "-9" is the only value between -10 and -8. At this point, the function cuts the x-axis, or the point where "f(x) = 0".

correct choice B