Answer:
divison
Step-by-step explanation:
3x=81
3x/3=81/3
Answer: Choice D) 
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Work Shown:

Explanation:
First I subtracted y/b from both sides. Then I multiplied both sides by 'a' to fully isolate x. You can optionally distribute the 'a' through to each term inside the parenthesis, but your teacher has chosen not to do this.
Answer:
Option D is correct
Step-by-step explanation:
The identity matrix is the matrix, in which, the diagonal elements are 1 and all of non-diagonal elements are 0.
Hope this helps!
Answer:
$180
Step-by-step explanation:
To solve, we can set up a proportion and solve.
You earn $45 for 7.5 hours of work, and you earn $ x for 30 hours of work
45/7.5=x/30
Cross multiply
45*30=7.5*x
1350=7.5x
To solve for x, we need to get x by itself. It is being multiplied by 7.5. To undo this, divide both sides by 7.5
1350/7.5=7.5x/7.5
180=x
So, for 30 hours of work, you would earn $180
Answer:
(x + 39) or x = -39
Step-by-step explanation:
Set f(x) to 0
0 = 5x + 195
5x = -195
x = -39