= -2? i dont really know either
A, B, D are functions.
(First, second, and fourth response)
You can see which is function since for everyone input only has one value. You can also use the vertical line test.
Step-by-step explanation:
X + 9= 7
get x by itself you -9 on both sides
X + 9 = 7
- 9. -9
X = -2
All good and for number 6 you should draw an acute angle