Perform the indicated operations:
(8x2 – 2x + 11) – (-9x2 – x – 6) – (x2 + 2x – 5)
This is what I did (not sure if I'm right):
Performed distributive operations for like terms:
8x^2 – 9x^2 – x^2 = -2x^2
-2x – x + 2x = 1x
11 – 6 – 5 = 0
Answer: -2x^2 + 1x + 0 (or, -2x^2 +1x)
My own check (vertically):
8x^2 – 2x + 11
-9x^2 – 1x - 6
-------------------
-1x^2 – 1x + 5
-1x^2 – 1x + 5
- x^2 + 2x – 5
--------------------
-2x^2 + 1x + 0
Answer: -2x^2 + 1x
Is that right?
2007-03-03 13:59:57 · 7 answers · asked by Brackish 1 in Science & Mathematics ➔ Mathematics
No, it isn't right. When you add like terms, don't forget that there is a minus sign in front of the whole 2nd term in brackets so the sign changes, for example you did 8x^2 – 9x^2 – x^2 but it should be 8x^2 + 9x^2 – x^2, for your second line, it should be +x and for the third line, it should be +6. Two negatives make a positive. The answer is 16x2 - 3x + 22.
2007-03-03 14:11:16 · answer #1 · answered by Jay 1 · 0⤊ 0⤋
Actually I think the answer should be 16x^2 - 3x + 22 because you have to distribute the - into the (-9x^2-x-6) and that makes that whole polynomial positive so it is like you are adding 8x^2 - 2x + 11 + 9x^2 + x + 6 - x^2 - 2x + 5 and if I did my math right it equals 16x^2 - 3x + 22
2007-03-03 22:11:34 · answer #2 · answered by soccer 2 · 0⤊ 0⤋
You've got a - (-9x^2 - x - 6)
When you distribute the outside "-" into the parentheses, it changes the sign of each. In other words:
+ (9x^2 + x + 6)
Same thing with the last grouping:
+ (-x^2 - 2x + 5)
Does this help?
Work it out again, and the answer you should get is:
16x^2 - 3x + 22
2007-03-03 22:09:38 · answer #3 · answered by Dave 6 · 0⤊ 0⤋
(8x2 – 2x + 11) – (-9x2 – x – 6) – (x2 + 2x – 5)
8x2 + 9x2 - x2 -2x + x - 2x +11+6+5
16x^2 - 3x + 22 is the answer if all you are doing is combining like terms. You forgot to distubute the -1 to the 2nd and 3rd set.
2007-03-03 22:12:51 · answer #4 · answered by closetcoon_fan 5 · 0⤊ 0⤋
i do my algebra a little more linear than you
getting rid of the brackets leaves all terms like this:
8x^2 - 2x +11 +9x^2(remember sign changes) +x +6 -x^2 -2x +5
grouping like terms gives you this:
16x^2 -3x +22
that will be your final answer. (no common factors, etc)
2007-03-03 22:10:28 · answer #5 · answered by Chubbs20 2 · 0⤊ 0⤋
okay. i got :
(8x^2 + 9x^2 - x^2) = (17x^2 - x^2) =16x^2
(-2x +(-2x)+x)= (-4x + x)= -3x
(11 +6+ 5) = (17 + 5) =22
so the answer i got was
16x^2 - 3x +22
2007-03-03 22:13:36 · answer #6 · answered by Taylor R 1 · 0⤊ 0⤋
16x^2-3x+22
2007-03-03 22:26:18 · answer #7 · answered by rwbblb46 4 · 0⤊ 0⤋