Adding and Subtracting Polynomials??

Question

Adding and Subtracting Polynomials??

Simplify all of the following please.

(ab - 9) - (6ab + 8)

A. ab + 17

B. ab - 9 - 6ab - 8

C. -6ab + 17

D. -5ab - 17

(x-9) + (x^2 - x + 17)

A. x^2 + 8

B. x - 2

C. x^2 - 17

D. x + 9

Answer 1

When adding and subtracting polynomials, you have to find like terms.  For example in the first question, (ab) and (6ab) are like terms.  ab - 6ab = -5ab, and -9 - 8 = -17.  So the answer is D. -5ab - 17.

In the second one, x and -x, and -9 and 17 are like terms.  x^2 has no other like terms in the second grouping, so you get: x^2 + (x + -x) + (-9 + 17) = x^2 + 0 + 8 = x^2 + 8, D.

Answer 2

D

A

Answer 3

with adding and subtracting polynomials, you can take out the parenthesis as long as there is only addition and subtraction. just distribute the distraction sign.

(ab - 9) - (6ab + 8) (distribute the - sign and solve.)

-5a-17

(x-9) + (x^2 - x + 17) (just add)

x^2+8

Answer 4

1. You can only add/subtract like terms

(ab-9) - (6ab+8)

Distribute the negative sign first.

ab - 9 -6ab -8

Group like terms and simplify

(ab-6ab) + (-9 - 8)

-5ab - 17

D

2. Group like terms. Simplify.

x2 + (x-x) + (17-9)

x2 + 8

A

Answer 5

ab-9

-6ab-8

---------

-5ab-17

x-9

x^2-x+17

x^2+8

Answer 6

for the first one its C. -6ab+17

for the second one is A, x^2 + 8  

absolutely positive !  

Answer 7

okay, here are the steps

(ab-9) - 1(6ab + 8)    Distribute the negative invisible one and change subtraction to addition (no such thing as sub. in algebra)

[ab+ (-9)] + [-6ab + (-8)]     add like terms

-6ab+ ab    +      -9+-8

-5ab-17 (D)

(x-9) + (x^2-x+17)   sub to add.

[x+ (-9)] + [x^2 +(-1x) +17]    add like terms

X^2   +     x+-x     +    -9+17

x^2+8 (A)

Try doing your homework next time okay?