Question:
Solution:
Let the following equation:
![\sqrt[]{12-x}=\text{ x}](https://tex.z-dn.net/?f=%5Csqrt%5B%5D%7B12-x%7D%3D%5Ctext%7B%20x%7D)
this is equivalent to:
![(\sqrt[]{12-x})^2=x^2](https://tex.z-dn.net/?f=%28%5Csqrt%5B%5D%7B12-x%7D%29%5E2%3Dx%5E2)
this is equivalent to:

this is equivalent to:

thus, we can conclude that
x= 3.
Answer: I think 7
Step-by-step explanation:
#1 7.1 years old
#2 7.8 years old
#3 87.4
#4 74
#5 7.4
3/4 is 0.75 as a decimal so 4 x 0.75 = 3
A. (x+3)(4x+5)
(multiply x with 4x+5 then multiply 3 with 4x+5)
=4x^2+5x+12x+15
=4x^2+17x+15
b,c, and d are similar