which of the following is an even function?\n○ (f(x)=(x - 1)^2)\n○ (f(x)=8x)\n○ (f(x)=x^2 - x)\n○ (f(x)=7)

Explanation:

Step1: Recall the definition of an even function

A function $f(x)$ is even if $f(-x)=f(x)$ for all $x$ in the domain of $f$.

Step2: Check $f(x)=(x - 1)^2$

$f(-x)=(-x - 1)^2=(x + 1)^2\neq(x - 1)^2=f(x)$.

Step3: Check $f(x)=8x$

$f(-x)=8(-x)=-8x\neq8x=f(x)$.

Step4: Check $f(x)=x^2 - x$

$f(-x)=(-x)^2-(-x)=x^2 + x\neq x^2 - x=f(x)$.

Step5: Check $f(x)=7$

$f(-x)=7=f(x)$ since for any value of $x$ (whether positive or negative), the function value is 7.

Answer:

$f(x)=7$