## The function f is defined by $$f(x)=\sqrt{x}-10$$ for all positive numbers x. If u=f(t) for some positive numbers t and

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### The function f is defined by $$f(x)=\sqrt{x}-10$$ for all positive numbers x. If u=f(t) for some positive numbers t and

by AAPL » Mon Jun 14, 2021 4:45 am

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## Global Stats

Official Guide

The function f is defined by $$f(x)=\sqrt{x}-10$$ 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. $$(u^2+10)^2$$

OA D

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### Re: The function f is defined by $$f(x)=\sqrt{x}-10$$ for all positive numbers x. If u=f(t) for some positive numbers t

by [email protected] » Mon Jun 14, 2021 8:29 am
AAPL wrote:
Mon Jun 14, 2021 4:45 am
Official Guide

The function f is defined by $$f(x)=\sqrt{x}-10$$ 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. $$(u^2+10)^2$$

OA D
f(x) = √x - 10
So, f(t) = √t - 10

So, if u = f(t), then we can write: u = √t - 10
Add 10 to both sides: u + 10 = √t
Square both sides: (u + 10)^2 = (√t)^2
Simplify right side: (u + 10)^2 = t