90 trucks- for every 2 cars there are 5 trucks
The equation (1) is divided by 2 to create new equivalent system of equations.
Step-by-step explanation:
The given systems of equations are:

Considering 8y instead of 8 in eq(1)
We need to identify what action was completed to create this new equivalent system of equations? 
Comparing given equations we came to know that equation(1) is divided by 2 to get the new equation i.e

While second equation is same as given.
So, The equation (1) is divided by 2 to create new equivalent system of equations.
Keywords:System of Equation
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It’s the heigh. Times the radius and volume
h= V/r
Notice that x+4 is one of the denominators, and that x(x+4) is the LCD.
x
Thus, mult. ------- by x(x+4), obtaining x^2.
x+4
Next, mult. [ 1/x + 1/(x+4) by x(x+4), obtaining x+4 + x = 2x+4 or 2(x+4)
x^2
Then the simplified fraction becomes ----------
2(x+4)
Generally Brainly allows you to post only 1 or 2 questions at a time. I will do #15 as a courtesy to you, but want you to try #16 yourself (or to post it separately).
-4, 2, 8, 14, ... is an arithm. seq. Every new term is equal to the previous term, plus 6: -4+6 = 2; 2+6=8, and so on. Thus: first term is a = -4; common difference is d = 6
a(50) = a(1) + (50-1)(6), or a(50) = -4 + (49)(6) = 290 (answer)
356/8 = 44.5
44.5 miles/hour
44.5 miles per hour