-13y+20=-8y-25

Question

How do you solve this problem

Answer 1

I added 13y to both sides and got 20=5y-25.  Adding 25 to both sides gives 45=5y so y=9.

Answer 2

Let's start by getting all the variable terms on the left side of the equation and constant terms on the right. To do that, we always apply the opposite operation to the term we're interested in; additionally, to maintain the equality, what we do to one side we always do to the other. Let's get the -8y term to the left side by adding 8y to each side then combine like terms.

-13y + 20 = -8y - 25
+8y          +8y
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-5y + 20 = -25

Now, let's subtract 20 from each side.

-5y + 20 = -25
      -20     -20
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-5y = -45

What is the operation occurring between the -5 and y? Multiplication. So we do the opposite. Let's divide each side by -5 so that the coefficient of y goes to 1 (we are only interested in what y is equal to, not -5y).

-5y = -45
-5       -5

The -5/-5 = 1, so y = -45/-5 = 9

Answer 3

Oopse, I mistyped out the steps, here's the corrected version:

1. Isolate the variable terms (those with y) and the constant terms. In other words, get the variable terms on the left side of the equal sign, and get the numbers on the right side.

Add 8y to both sides

-5y + 20 = -25

Subtract 20 from both sides

-5y = -45

2. To solve for y, divide both sides by -13

y = 9

Hope this helps!