Question

7. Solar heat costs $30,000 for installation plus $150 per year to operate. Electric heat costs $5000 for installation plus $1100 a year to operate. Graph your two equations. How long will it take the solar heat to cost the same as the electric? solve for x and y

Answer 1

Solar heat

Installation= $30,000

Cost per year = $150

Electric heat

installation = $5000

Cost per year = $1100

Years: x

Equations:

Solar heat:

y = 150x+30,000

Electric heat

y= 1100x+5,000

Equal both equations:

150x+30,000=1100x+5,000

Solve for x

30,000-5,000 = 1100x-150x

25,000= 950x

25,000/950 =x

26.31 =x

26 years

Replace x on any equation

y = 150(26)+30,000

y= $33,900