- Using
substitution
means you are going to solve one equation for one variable and substitute with
its value in the other equation in order to get also an equation with one
variable.
Answer:
see below
Step-by-step explanation:
1st: x
2nd: 5x + 8
x(5x + 8) = 36
5x² + 8x = 36
5x² + 8x - 36 = 0
(x - 2)(5x + 18) = 0
(x - 2) = 0
x - 2 = 0
x = 2
1st: x = 2
2nd: 5x + 8 = 5(2) + 8 = 18
(5x + 18) = 0
5x + 18 = 0
5x = -18
x = -3.6
1st: x = -3.6
2nd: 5x + 8 = 5(-3.6) + 8 = -18 + 8 = -10
<span>10x + 30(2) = 20(x + 2)
10x + 60 = 20x + 40
10x = 20
answer
x = 2 liters
So you would need 2 liters of the 10% solution to make the 30% solution 20%.</span>
Answer:
240kmh
Step-by-step explanation:
The distance that the train traveled in 30s is the difference of the total length of the tunnel and the train (2000m). This means it travels 2000m/30s. This ratio is the same as 240000/3600s or 240km/1hr.
