Answer
(a) $f(9)=29$
(b) $x=\frac{5}{4}$ or $f(\frac{5}{4})=-2$
(c) Domain of $f(x)$: $(-\infty,\infty)$
Range: $(-\infty,\infty)$
Work Step by Step
$f(x)=4x-7$
(a) Put $x=9$ in the equation:
$f(9)=4\times9-7=29$
(b) Putting $f(x)=-2$
$4x-7=-2$
$4x=5$
$x=\frac{5}{4}$
$f\left(\frac{5}{4}\right)=-2$
(c) Since $f(x)$ is a linear function, therefore defined for all real numbers, Domain of $f(x)$:
$(-\infty,\infty)$
Similarly the range will be
$(-\infty,\infty)$
