12 is B. You because the graphs slope is 1. 13 is A 7 I think.
1.) 40, 2.) 8, 3.) 18, 4.) 15, 8.) 12, 9.) 30, 10.) 72, 11.) 36
Cost of Lightbulb = x
cost of switch is x-8
9x + 4(x-8) = 520.50
Use distributive property:
9x + 4x -32 = 520.50
Simplify:
13x -32 = 520.50
Add 32 to both sides:
13x = 552.50
Divide both sides by 13
X = 42.50
A lightbulb costs $42.50
A switch costs 42.50-8 = $34.50
I believe the answer is c ,BECAUSE... to find the change you take 5000 multiply it by the numbers that if aded would equal 5600 and 5000 times .12= 600, 5000 +600= 5600 hence the number of population in 2010.
hope I helped
