Answer:
5
Step-by-step explanation:
this is basic algebra so it's important to understand this concept now. you need to combine like terms so 3x-6=9 becomes 3x=15 (you add the 6 to add like terms). You then divide the 3 from 3x on both sides to get x=5
f(-3)= -(-3)^2+6= -9 + 6 = -3
