13. EARNINGS The original price of a model car is d dollars. You use a coupon and buy the kit for (d − 10) dollars. You assemble the model car and sell it for (2d − 20) dollars. Write an expression that represents your earnings. Interpret the expression.

(d − 10); You earn (d − 10) dollars. You also paid (d − 10) dollars, so you doubled your money by selling the model car for twice as much as you paid for the kit.

$450

step-by-step explanation:

first, you have to multiply 150x2=300

next, you have to add 150+300= 450

infinitely many solutions

step-by-step explanation:

we have been given the equation;

2(2x + 3) = -4 + 2(2x + 5)

we need to determine the value of x.

2(2x + 3), we expand this expression to obtain 4x + 6

similarly 2(2x + 5) will become 4x + 10

now we have;

4x + 6 = -4 + 4x + 10

4x + 6 = 4x + 10 - 4

4x + 6 = 4x + 6

the expression on the left hand side is identical to the one on the right hand side. therefore, we are looking at just a single straight line whose equation is;

y = 4x + 6

consequently, we shall have infinitely many solutions