I'm suppose to simplify:
-(3x-y)+3(2y-3x)
my answer is:
7y+12x
Is that right? I get lost with whether to use + or - sometimes.
-3x + y + 6 y - 9 x
-12 x + 7 y
-(3x-y) +3(2y-3x)
-3x + y + 6y + -9x
7y + -12x
As Damon said.
To simplify the expression -(3x-y)+3(2y-3x), you should follow the steps of combining like terms and applying the distributive property if necessary.
1) Start by distributing the 3 to the terms inside the parentheses: 3(2y-3x) becomes 6y-9x.
The expression becomes: -(3x-y) + 6y - 9x
2) Next, simplify the terms inside the parentheses, -(3x - y) becomes -3x + y.
The expression becomes: -3x + y + 6y - 9x
3) Now, combine like terms by adding or subtracting coefficients of similar variables. In this case, we have -3x and -9x, which can be combined to give -12x. Additionally, we have y and 6y, which can be combined to give 7y.
The simplified expression is then: -12x + 7y. Therefore, your answer should be -12x + 7y instead of 7y + 12x.
Remember to carefully apply the signs when combining terms. In this case, the terms with x have negative signs in front of them, so be sure to include those signs when combining them.