Answer:
126
Step-by-step explanation:
Answer:
a +b = 2
Step-by-step explanation:
a +3 = 6
a = 6 -3
a = 3
Plugin a =3 in the equation,
a*b +5*a +3*b + 15 = 24
3b + 5*3 + 3b + 15 = 24
3b + 15 + 3b + 15 = 24 {combine like terms}
3b + 3b + 15 + 15 = 24
6b + 30 = 24 {Subtract 30 from both sides}
6b = 24 -30
6b = -6 {divide both sides by 6}
b = -6/6
b = -1
a + b = 3 + ( -1)
= 2
14)
2(-3)² => 2(-3)(-3) => 2*9 = > 18
27+18-11 => 27 + 7 = > 34.
16)

17)

Answer:
1.42 hours
Step-by-step explanation:
In this case we must take into account that the speed would be to fill a pool for a time, that this case is in hours, therefore it would be like this:
1/5 for the first pipe
1/2 for the second pipe
Now, we will use both at the same time, therefore:
1/5 + 1/2 = 1 / x
0.7 = 1 / x
x = 1 / 0.7
x = 1.42
That is to say that if we use both we will take a total of 1.42 hours
See attached picture for answer: