Answer: 120x4+270
Step-by-step explanatio:
Umm so I’m only in 8th grade and this was on my test so the 4 is an exponent
Solving for a variable in an equation means, we are changing the subject of formula of the equation.
The equation of r is: 
The equation is given as:

We start by multiplying both sides by 3

Rewrite as:

Divide both sides by 

Cancel out common factors

Take square roots of both sides

Evaluate the right-hand sides

Make r the subject

Hence, the resulting equating for r is:

Read more about the subject of formulas at:
brainly.com/question/21866313
Answer:
Step-by-step explanation:
-6x=24
+6 +6
x= 30
Answer:
f(3) = -20
Step-by-step explanation:
To find the value of a function, substitute the number for the variable and do the arithmetic.
f(x) = -2x^2 +x -5 . . . . . . given
f(3) = -2(3^2) +(3) -5 . . . . function value for x = 3
f(3) = -2(9) +3 -5 = -18 +3 -5
f(3) = -20