the problem is about adding and subtracting polynomials...

Question

This is what I did...

2x+3+3x+1
=2x+3x+3+1
=5x+4

and

9x+11-5x+4
=9x-5x+11+4
=4x+15

but then, if I add both 5x+4+4x+15
=9x+19...

Answer 1

I think this deals with the same problem you posted at 8:49 pm

In this question I think you wanted to subract 5x+4 from 9x+11

that would be 9x+11 - (5x+4)
= 9x + 11 - 5x - 4
= 4x + 7

See how important brackets and the order of operations are ??

Answer 2

(9m + 6) + (-5m - 6)

Answer 3

= (9m - 5m) + (6 - 6)
= 4m + 0
= 4m

Answer 4

(3r² + 7r + 1) + (4r² - 8r - 2)

Answer 5

(3r² + 7r + 1) + (4r² - 8r - 2)

= 3r² + 4r² + 7r - 8r + 1 - 2 (grouping like terms)

= 7r² - r - 1

Answer 6

(6h + 1) - (9h + 4)

Answer 7

(6h + 1) - (9h + 4)

= 6h + 1 - 9h - 4 (distribute the negative sign to all terms inside the parentheses)

= -3h - 3

Answer 8

(-7w² - 2w - 1) - (-5w² + 3w - 2)

Answer 9

(-7w² - 2w - 1) - (-5w² + 3w - 2)

= -7w² - 2w - 1 + 5w² - 3w + 2 (change the signs inside the second set of parentheses and combine like terms)

= -2w² - 5w + 1