Answer:
c. -x + 3x + 7 = 2x+7
Step-by-step explanation:
f(x) = 3x +1 and g(x) = x - 6
f-g = 3x +1 - ( x - 6)
Distribute the minus sign
= 3x+1 - x+6
= 2x +7
We know that Heidi has x donations. We also know that Granpa has 2 fewer donations than Heildi, which means to subtract so x - 2. We also know that there are 7 donations in all. This tells use donations = 7 in all. So
Heidi donations = x
Grandpa = x - 2
Heidi + Grandpa = Total donations
x + (x-2) = 7