Here is your answer wish you good luck
The coefficients are -7, 8, -3, 1, and -9
The answer is 15% of $2.55=$0.3825=$0.38 off
Step by step: Take 15% and divide 15% by $2.55 This will give you the amount of money that is going to be added onto the bill. When you divide it and get your answer just add the answer to your original bill.
The answer to your question is y=-7
You can simply collect terms, subtract the constant and divide by the x-coefficient. It is generally considered easier to do those steps if you eliminate fractions first (multiply by 12).
Multiply by 12
... 4(x -1) +3(x +5) = 6
... 4x -4 +3x +15 = 6 . . . . . eliminate parentheses
... 7x +11 = 6 . . . . . . . . . . . .collect terms
... 7x = -5 . . . . . . . . . . . . . . subtract the constant 11
... x = -5/7 . . . . . . . . . . . . . divide by the x-coefficient
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Here it is the other way.
... x(1/3 +1/4) +(-1/3 +5/4) = 1/2
... (7/12)x + 11/12 = 1/2 . . add the fractions to finish collecting terms
... x + 11/7 = 6/7 . . . . . . . multiply by 12/7
... x = -5/7 . . . . . . . . . . . subtract 11/7
At the third step here, you could subtract 11/12 before doing the multiply. You get the same answer, but you have to do the extra conversion of 1/2=6/12.