Question

I need to know how to do a)^

Answer 1

a)

he charges a fixed cost of $12, meaning a one-time charge of 12 bucks, plus 1.50 for each window.

1 window................ 12 + 1.5(1)

2 windows............. 12 + 1.5(2)

3 windows............. 12 + 1.5(3)

4 windows............. 12 + 1.5(4)

x windows............. 12 + 1.5(x)

$\bf \stackrel{cost}{y}=\stackrel{\stackrel{fixed}{cost}}{12}+\stackrel{\stackrel{per}{window}}{1.5x}$

b)

$\bf \stackrel{cost}{28.50}=\stackrel{\stackrel{fixed}{cost}}{12}+\stackrel{\stackrel{per}{window}}{1.5x}\implies 16.50=1.5x\implies \cfrac{16.50}{1.5}\implies \boxed{11=x}$