Answer:
5670
will be your answer!
Step-by-step explanation:
21 x 18 x 15 = 5670
(24·z^3)^2/(27·12·z) = (2^3·3·z^3)^2/(3^3·2^2·3·z) = (2^6·3^2·z^6)/(3^3·2^2·3·z) = 2^4·3^(-2)·z^5
a = 4 ; b = -2 ; c = 5
Here you have a system of 2 equations and 2 unknowns. An easy way to solve this type is to isolate one of the variables.
12a + 2b = 8
2b = 8 - 12a
b =

b = 4 - 6a
Now plug 4 - 6a into equation 1 to solve for a.
a + 5(4 - 6a) = 19
a + 20 - 30a = 19
-29a = -1
a = 1/29 (answer)
Now plug a into the equation for b
b= 4 - 6(1/29)
b= 110/29 (answer)
X/3=2
x=6
x/5=3
x=15
x/7=2
x=14
Each time, you multiply both sides by the denominator.
Hope this helps :)