Let's complete the right part of the equation first. When you say something is 13 more, you refer to addition (13+). The next part is six times a number. When we don't know what the "number" is, we'll refer to it as x. When they say six times, it refers to multiplication. Our left side of the equation would thus be 13+6x. The right part consists of the words "is -137". The word is refers to equal to. So that's just =-137. Our whole equation is 13+6x=-137. We can solve this expression by subtracting 13 over to -137, which would give you -150. Now you're left with 6x=-150. We would divide 6 over to both sides, leaving us with x=-25. We can double check to see if our answer is correct. First, we would multiply -25 by 6, giving us -150. Add -150 with 13 and we'll end up with -137, so our answer checks out.
