Question

3
bob earns $9 an hour working at the roller - skating rink and spends $2 per hour playing the pinball machine.
by the end of the week, he saved $84.
the equation shows the number of hours, h, bob worked last week.
$9h - 2h = 84$
how many hours did bob work last week?
a 12
b 16.5
c 18.25
d 24

Explanation:

Step1: Combine like terms

First, we simplify the left - hand side of the equation \(9h - 2h=84\). Since \(9h\) and \(- 2h\) are like terms, we can combine them. According to the rule of combining like terms (for terms with the same variable, we add or subtract their coefficients), we have \(9h-2h=(9 - 2)h = 7h\). So the equation becomes \(7h=84\).

Step2: Solve for h

To find the value of \(h\), we divide both sides of the equation \(7h = 84\) by 7. The formula for this step is \(h=\frac{84}{7}\). When we calculate \(\frac{84}{7}\), we know that \(7\times12 = 84\), so \(h = 12\).

Answer:

A. 12