Answer:
22
Step-by-step explanation:
if a=15
then, 2(a-5)+2= 2(15-5)+2 = 2(10)+2= 20+2=22
The first thing any good mathematician does is convert the measurements to the same unit as what the question is asking. In this problem, it states that the pool fills at a rate of 20 cubic meters per hour. Just keep in mind that an hour is 60 minutes.
The next step is to see how many cubic meters will cost $300. This can be done by dividing 300 by 10. This gets you 30 cubic meters of water.
You already know that 60 minutes is 20 cubic meters of water. That leaves the remaining 10 cubic meters of water. By dividing the rate given, you get that 30 minutes is 10 cubic meters of water. Add the 60 and 30 together to get 90 minutes.
It will take 90 minutes for the pump to use $300.
Answer:
Henry is 18 and Paul is 7
Step-by-step explanation:
I figured it out in my head.
<span>Simplifying
2x + 18y = 36
Solving
2x + 18y = 36
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '-18y' to each side of the equation.
2x + 18y + -18y = 36 + -18y
Combine like terms: 18y + -18y = 0
2x + 0 = 36 + -18y
2x = 36 + -18y
Divide each side by '2'.
x = 18 + -9y
Simplifying
x = 18 + -9y</span>
Answer:
B
Step-by-step explanation:
+ 6 = x ( subtract 6 from both sides )
= x - 6 ( square both sides )
x = (x - 6)² ← expand using FOIL
x = x² - 12x + 36 ( subtract x from both sides )
0 = x² - 13x + 36 , that is
x² - 13x + 36 = 0 ← in standard form
(x - 4)(x - 9) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 4 = 0 ⇒ x = 4
x - 9 = 0 ⇒ x = 9
As a check
Substitute these values into the equation and if both sides are equal then they are the solutions.
x = 4
left side = 
+ 6 = 2 + 6 = 8
right side = x = 4
Since 8 ≠ 4 then x = 4 is an extraneous solution
x = 9
left side = 
+ 6 = 3 + 6 = 9
right side = x = 9
Thus the solution is x = 9 → B
