ACT red book math problem?

<p>For test 1.</p>

<p>If x is a real number such that x^3 = 64, then x^2 + square root x.</p>

<p>4
10
18
20
47</p>

<p>The answer key: 18</p>

<p>To find out what x^2 + square root x equals, you need to solve x^3 = 64 for x. The solution is ^3 square root 64, which is 4. Then, subsituting into the original expression, you get 4^2 + square root 4. This expression simplifies to 16 + 2, or 18.</p>

<p>How do they get the 3^ square root 64 is 4? I don’t understand this.</p>

<p>4x4x4=64
4 is x</p>

<p>square root of 4 = 2
4 squared = 16 </p>

<p>16+2=18</p>

<p>4 * 4 * 4 = 64.</p>

<p>It’s called a “cube root.”</p>

<p>And 4<em>4</em>4 = 64.</p>