Question

1.

10a – 8b

(-) 4a + 5b

2.

5b + 3c

(-) 4b + 3c

3.

6d + 6e

(-) 9d – 8e

4.

8x – 3y

(-) -4x + 8y

5.

6rs – 7bc

(-) 9rs – 7bc

6.

5xy – 9cs

(-)-3xy + cs

7.

x2 – 6x + 5

(-) 3x2– 2x – 2



8.

3y2 – 2y – 1

(-) -5y2– 2y + 6

9.

(7a + 6b – 9c) – (3a – 6c)

10.
(x2 – 9) – (-2x2 + 5x – 3)

11.

(5 – 6d – d2) – (-4d – d2)

12.

(-4x + 7) – (3x – 7)

13.

(4a – 3b) – (5a – 2b)

14.

(2c + 3d) – (-6d – 5c)

15.

(5x2 + 6x – 9) – (x2 – 3x +7)

16.

(3y – 6) – (8 – 9y)

17.

(3a2 – 2ab + 3b2) - (-a2 – 5ab + 3b2)

18.

5c – [8c – (6 – 3c)]

19.
10x + [3x – (5x – 4)]

20.

3x 2 – [7x- (4x – x2) + 3]

21.

x2 – [ - 3x+ ( 4 – 7x)]
Some one please help I don't understand how to do this it says to subtract the polynomials but I don't understand!

Answer 1

Yikes!

Answer 2

You must group terms with like exponents. For example,

#20

3x^2 – [7x- (4x – x^2) + 3]
= 3x^2 - [7x-4x+x^2+3]
= 3x^2 - [x^2+3x+3]
= 3x^2-x^2-3x-3
= 2x^2-3x-3

You can see this at this url:

http://www.wolframalpha.com/input/?i=3x^2+%E2%80%93+[7x-+%284x+%E2%80%93+x^2%29+%2B+3]

now type in your other expressions to verify your answers.