Answer:
-21
Step-by-step explanation:
3x7=21 and a negative x a positive is always negative
If you plug in the x and y of choice b you would see that it does not equal 18.
6(3) + 3(-1) = 18
18 + (-3) = 15
Answer:
the answer is 18. There are 18 ways to arrange the cars.
Bu using Pythagoras theorem
(x^2)+(21)^2=(75)^2
Therefore. 5625-441=(x)^2
X^2=5184
Therefore x=72
Third side length=72 units