Answer: x is 12
Step-by-step explanation:
For directly proportional relationship, both variables change in the same direction. It means that an increase in one variable will result to an increase in the other variable. A decrease in one variable will result to a decrease in the other variable.
y and x have a proportional relationship,
We will introduce a proportionality constant and replace the proportionality symbol with an equal to symbol. Thus
y = kx
When y is 12, x is 8
Substituting into the equation,
12 = k × 8
k = 12/8 = 1.5
The equation becomes
y = 1.5x
The value of x when y is 18 will be
18 = 1.5x
x = 18/1.5 = 12
Round to the nearest percent
2(x+7)+3(x+1)
= 2x+14+3x+3
= 5x+17
