Question

Explain the ErrorFind the error in the solution, and then solve it correctly.7x + 21 + 3x = 27x + 21 = -17x = -22X=-227(select) was subtracted from the left side, but (select) was subtracted from the right side. TheSubtraction Property of Equality states that you can subtract the same number from each side and theequation will remain true. But 3x and 3 are not the same number (unless x is 1X =

Answer 1

Okay so the given equation is:

$7x+21+3x=2$

now the rule is that what ever you do on the right-hand side you have to do the same on the left-hand side. But remember! You can not subtract or add digits from variables, such as x.

Now in order to solve x, let us add like terms on RHS and subtract 21 from both sides to get:

$10x=-19$