I need help please, especially on #2

Answer:
1a No because x cannot have more than one y value
1b domain is 0≤x≤4 range is 0≤y≤2
2a ƒ(-4)=15 = -2(-4)+7
2b x=15 => -23=-2(x)+7 => -30=-2(x) => 15=x
Answer:
#2
a= 15
b= 15
Step-by-step 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.