Question

Which of the following functions are increasing?

f(x)=7
f(x)=x
f(x)=8x+7
f(x)=−6x+7
f(x)= 1/5x+7
f(x)= −1/9x+
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Answer 1

The following functions are increasing:

f(x) = x
f(x) = 8x + 7
f(x) = 1/5x + 7

To tell if a function is increasing, its slope must be positive. In all the listed functions, the slope is a positive number. In f(x) = 7, the slope is 0 meaning it does not increase. In f(x) = -6x + 7, there is a slope of -6, signifying a decline. Finally, in -1/9x, the slope is -1/9, meaning it declines.