Getting frustrated w/Algebra text mistakes, please check....

[LearnFromHome]

We keep doing problems and I'm finding mistakes after mistakes...I would like to confirm that we are not wrong. Please check if this problem is wrong for my son's sake.

Thanks you, thank you!

7a-5b/2a+3b - 9a-2b/2a+3b= -1(2a+3b)/2a+3b= -1

my son's answer is 7b/3b very different.

[8FillTheHeart]

We keep doing problems and I'm finding mistakes after mistakes...I would like to confirm that we are not wrong. Please check if this problem is wrong for my son's sake.

Thanks you, thank you!

7a-5b/2a+3b - 9a-2b/2a+3b= -1(2a+3b)/2a+3b= -1

my son's answer is 7b/3b very different.

The text answer is correct.

The problem actually becomes

7a-5b-9a+2b (all that is required is that you distribute the - across the numerator since they have common denominators)
divided by 2a + 3b=

-2a-3b/2a+3b

Factor out a -1 and the numerator and denominator eliminate leaving you with -1.


FWIW....if your son's answer were correct, the bs would cancel each other out leaving you with 7/3.

[Jann in TX]

Have your son put a parenthesis around the complex numerator of the second fraction. This way he can 'see' that he needs to distribute that pesky negative/subtraction sign!

Top would be more like this:
7a - 5b - (9a - 2b)