In solving the linear equation 5x – 9 = 3x + 3, a student wrote 5x + 3x – 9 = 3x – 3x + 3 as the next step. Identify mistakes.

Sagot :

5x - 9 = 3x + 3
To eliminate 3x from the right side, subtract each side of the equation with 3x
5x - 3x - 9 = 3x - 3x + 3
Notice the difference between what i wrote and the one that the student wrote.. 
Instead of subtracting 3x to the right, he/she added instead. The mistake is the operation used. It should be minus(-) not plus (+).
[tex]The \ given \ linear \ equation \ is; \\ \\ 5x-9=3x+3 \\ \\ Eliminate \ 3x \ on \ the \ right \ side \ to \ do \ the \ next \ step. \\ \\ 5x-3x-9=3x-3x+3 \\ \\ Notice \ the \ difference \ of \ my \ answer \ and \ the \ student; \\ \\ My \ answer; \\ 5x\boxed{-3x}-9=3x-3x+3 \\ \\ Student's \ answer; \\ 5x\boxed{+3x}-9=3x-3x+3 \\ \\ Hope \ it \ Help:) \\ Domini[/tex]