To restate the problem, we want to solve for the variable x and are given the equation: 7x-4=20x+2. Because x is on both sides, we need to isolate the variable. This means x needs to be on only one side of the equation. Here's how we'd work this question out! I'm going to bold and separate each number so it's easier to read!
The Equation: 7x - 4 = 20x + 2
Option 1 Step 1: 7x - 4 - 7x = 20x + 2 - 7x --> - 4 = 13x + 2
We can isolate the variable on either side of the equation. Here, we'll subtract 7x from both sides of the equation. The 7x and -7x will cancel out on the left side, leaving us with -4 on the left side. I personally like x being on the left-hand side, so I'll rewrite the new equation as the following.
13x + 2 = -4
Option 1 Step 2: 13x + 2 - 2 = -4 - 2 --> 13x = -6
To further isolate the variable, we need to get rid of the +2 on the side of the equation with x. To do this, we subtract 2 from both sides of the equation.
Option 1 Step 3: 13x ÷ 13 = -6 ÷ 13x --> x = -6/13
The last step to getting x completely by itself is getting rid of the coefficient of 13. We do this by dividing each side of the equation by 13.
Checking our work:
To check our work and confirm that it's correct, we plug -6/13 into the original equation for x.
7x - 4 = 20x + 2
7(-6/13) - 4 = 20(-6/13) + 2
-42/13 - 4 = -120/13 + 2
-42/13 - 52/13 = -120/13 + 26/13
-94/13 = -94/13
After checking our work, we can confirm that the value of x is -6/13.
Here's the second option for solving this equation without the extended explanation.
Option 2:
7x - 4 = 20x + 2
7x - 4 - 20x = 20x + 2 - 20x --> -13x - 4 = 2
-13x - 4 + 4 = 2 + 4 --> -13x = 6
-13x ÷ -13 = 6 ÷ -13 --> x = - 6/13
x = -6/13