David wanted to solve 3(x-7)=5. As a first step, he wrote 3x-21=15. What error did he make? Correct his error and then find the solution?

3(x-7)=5

3x - 21 = 5

3x = 21 + 5

x = 26/3

x = 8 2/3

Ok. so the error David make was putting 15 as the answerinstead of keep it as 5 correct?

Right.

Thank you Ms. Sue :))

You're welcome, Patchie. :-)

The error David made was that he distributed the 3 only to the x term but not to the -7 term. To correct this, we need to distribute the 3 to both terms inside the parentheses.

The correct equation should be:
3(x - 7) = 5
3x - 21 = 5

To solve this equation, we'll isolate the variable term (3x), and then solve for x.

First, we'll get rid of the constant term on the left side by adding 21 to both sides of the equation:
3x - 21 + 21 = 5 + 21
3x = 26

Next, we'll divide both sides of the equation by 3 to solve for x:
3x/3 = 26/3
x = 26/3

So, the solution to the equation 3(x - 7) = 5 is x = 26/3 or approximately 8.67.