Catherine S. answered • 01/29/19
Chemistry Tutor with Professional Scientific Experience
Hi Lay!
The trickiest part of solving these problems is to figure out what the problem looks like. To solve this problem, we must start with the important information given:
Twice the sum of a number and 7 is equal to three times the difference of the number and 7 .
- Twice the sum of a number (N) and 7: 2(N+7)
- Equal to: =
- Three times the difference of the number (N) and 7: 3(N-7)
Broken down into components, we can see 3 important parts in this problem. The left side of the equation, an equals sign, and the right side of the equation. This is the equation assembled from the components:
2(N+7) = 3(N-7)
To solve, we must find N. To find N, we need to get N by itself. We must use the distributive property on both sides of the equation to get N out of parenthesis.
2(N) + 2(7) = 3(N) - 3(7)
2N + 14 = 3N -21
The next step to get N by itself is to combine like terms. We want the variables together, and the whole numbers together. Start by subtracting 2N from each side.
2N - 2N + 14 = 3N-2N -21
14 = 1N -21
Lastly, we want the whole numbers together, on the opposite side of the variable. By adding 21 to each side, we will have N by itself on one side, and whole numbers on the other.
14 + 21 = N -21 + 21
? = N
Solve by adding the whole numbers together on each side of the equals sign to get your answer.
