Acar needs fixing and abe can fix it for $70 per hour with a $130 part, but gabe can fix it for $80 an hour with a $40 part. how long will it take for both abe and gabe to cost the same amount?

For the same amount set up two equations set equal to each other.
$70h + 130 = 80h + $40
Subtract 80h from both sides
-10h + 130 = 40
subtract 130 from both sides
-10h = -90 divide both sides by -10
h = 9 hours

CHECK
70(9) + 130 = $760 
80(9) + 40 = $760

First, think of what you know. you know that the number t the end of the equation will need to be subtracted because it is the money he lost from buying the lawn mower. and your first two weeks have negative profit, so that tells you that c and d are wrong. now you can plug any of the weeks into a and b to see which one works. i'll start with plugging week 1 into a.this isn't right because it says your answer for week one should be -90.so now we need to try the same thing with b.this one got you the right answer, (sometimes if you only check with one of the weeks multiple will work so you need to check with more of the weeks, but it worked out fine here)this means that b is the correct answer.let me know if you need more clarification. i hope this : )