Question

Help me subtract this problem.
[(4x)/2x-7]-[(x-7)/2x-7]

Answer 1

I put my final answer as \[\frac{ 3x-7 }{ 2x-7}\] but I got it wrong because it says that the answer is \[\frac{ 3x+7 }{ 2x-7}\] Why did I need to change the sign of 7?

Answer 2

@ashley_f97

Answer 3

\[ \frac{4x}{2x-7} - \frac{(x-7)}{2x-7}\]
both fractions have the same denominator, so you can subtract the numerators
\[ \frac{4x-(x-7)}{2x-7} \]

now notice you are doing 4x- (x -7)
the - subtracts *everything inside the parens*
it is the same as 4x -x - (-7)
the -(-7) becomes +7 (two minuses make a plus.

the top is 4x - x +7 or 3x+7

Answer 4

another way to do this is
4x - (x-7) is the same as
4x + -1*(x-7)
now "distribute" the -1, by multiplying both terms inside the parens by -1
4x + -1*x + -1*-7
simplify to 4x -x +7 and then 3x+7

Answer 5

Thank you!

Answer 6

yw