Answer:
For question #9:
For question #10: 
Step-by-step explanation:
Brainliest please!
Well I don't know !
Let's check out the choices:
A). 3a - 4b = 21, a=0, b=7
3(0) - 4(7) = 21
0 - 28 = 21 Nope. That's not true.
B). 3a - 4b = 21, a=-3, b=2
3(-3) - 4(-2) = 21
-9 + 8 = 21
-1 = 21 Nope. That's not right.
C). 3a - 4b = 21, a=-2, b=-3
3(-2) - 4(-3) = 21
-6 + 12 = 21
6 = 21 Nope. That's not it.
Only one choice left.
This one had better be it:
D). 3a - 4b = 21, a=7, b=0
3(7) - 4(0) = 21
21 - 0 = 21
21 = 21 Yay ! That's it !
Answer: x=7 and AC = 44 unuts.
Step-by-step explanation:
We know that the diagonals of a parallelogram bisect each other. (i)
Here in parallelogram ABCD , AC and Bd are diagonals intersecting at E.
BE = 2x + 2, BD = 5x – 3, and AE = 4x – 6
Using (i)

Now , AE = 4(7)-6 = 28-6 = 22
AC =2 AE = 2 (22) =44 units.
Hence, x=7 and AC = 44 unuts.
90-48=42
it won’t let me do short answer
Answer:
80 minutes
Step-by-step explanation:
* means multiply
make 1 hour into 60 minutes
3 miles/60 minutes = 4 miles/x minutes
3x = 240
x = 80