posted by bernadette .
If you are expected to solve for x, first multiply 0.7x * 4.
2.8x = 0.8x - 7
Subtract 0.8x from both sides of the equation to get x on one side. Whatever operation you do to one side of an equation you must do to the other side as well.
2.8x - 0.8x = 0.8x - 0.8x - 7
2x = -7
Now divide both sides by 2 to get x by itself.
2x/2 = -7/2
x = -7/2 = -3.5 (decimal form)
You can check this answer with the original equation. It always helps to check your work!