Answer:
#2
a= 15
b= 15
Explanation:
For 2a, x is -4 so you have to plug it into the equation
f(-4)= -2(-4)+7
f(-4)= 8+7
f(-4)= 15
For 2b it's telling you that f(x) equal -23
-23= -2x+7
Subtract 7 from both sides
-30=-2x
Divide both sides by -2
x=15
I hope this helped, if not i'm sorry.