Answer:
Firstly, rewrite the equation:
⅓ (18 + 27) = 81
Substitute x for the given number of it's supposed equivalent.
In this case x = 12.
⅓ (18(12) + 27) = 81
Solve using PEMDAS and simplify what is in the parenthesis first. Then, multiply.
(18 x 12) + 27 = 243
Now, solving using PEMDAS, multiply the total of what you got that was originally in the parenthesis by ⅓ .
⅓ (243) = 81
When you multiple these number they are equivalent to 81.
81 = 81
Since the equation given, when substituted x for 12, is equivalent to 81, this proves that substituting x for 12 makes this equation true.
Substitute -3 to x
(-3)^2 + 4(-3) + 1
9 - 12 + 1
= -2
Answer:
pages
Step-by-step explanation:
Divide the total number of pages by 5 to get how many sets of every 5 pages will contain 2/3 of a page of advertisements.

Multiply this value by
to get the total number of pages.
pages
The equation for the circumference is 2*pi*radius
if you are given the circumference then divide both sides by pi
that is because the diameter is 2 times the radius
so you can rearrange the equation to
C = pi * 2 * r
C = pi * d
divide both sides by pi
C/pi = d
Hope this helps :)