Question

The function f is defined by $f\left(x\right)=\sqrt{x}-10$ for all positive numbers x. If u = f(t) for some positive numbers t and u, what is t in terms of u?

• A. $\sqrt{\sqrt{u}+10}$
• B. ${(\sqrt{u}+10)}^2$
• C. $\sqrt{u^2+10}$
• D. ${(u+10)}^2$
• E. ${(u^2+10)}^2$

Answer 1

The correct option is D ${(u+10)}^2$

Given,

u = $\sqrt{t}-10$

Therefore,

u + 10 = $\sqrt{t}$

Squaring both sides,

t = (u + 10 ) ${}^2$