2007-05-14 08:19:45 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
(5x^2 - 2x - 1) - (3x^2 - 5x + 7)
= (5 - 3)x^2 + (-2 -(-5))x + (-1 - 7)
= 2x^2 + (-2 + 5)x + (-8)
= 2x^2 + 3x - 8.
2007-05-14 08:24:48 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Remember that the minus sign before parentheses changes the signs of the terms in the parentheses. So, you get:
5x^2-2x-1-3x^2+5x-7 = 2x^2+3x-8
2007-05-14 08:26:40 · answer #2 · answered by RG 3 · 1⤊ 0⤋
This is really easy if you remember that any minus sign before a bracket is considered the same as multiplying everything in the bracket by -1
eg. -(4x)=(-1)(4x)=-4x
or 1-(4x)=1+(-1)(4x)=1+(-4x)=1-4X
or 1-(4x+2)=1+(-1)(4x+2)=1+(-4x-2)=1-4x-2
so following that logic:
(5x^2-2x-1)-(3x^2-5x+7)
is the same as:
(5x^2-2x-1)+(-1)(3x^2-5x+7)
which is:
5x^2-2x-1+(-3x^2+5x-7)
(keep in mind that a positive times a negative is a negative and a negative times a negative is a positive)
So we end up with:
5x^2-2x-1-3x^2+5x-7
=2x^2+3x-8
Hope that helped you understand. If I wasn't clear about it let me know. Good luck! Math is pretty cool!
2007-05-14 08:31:29 · answer #3 · answered by alexk 2 · 1⤊ 0⤋
5x² - 2x - 1 - 3x² + 5x - 7 =
2x² + 3x - 8.
2007-05-14 08:24:28 · answer #4 · answered by S. B. 6 · 1⤊ 0⤋
(5x^2 - 2x - 1) - (3x^2 - 5x + 7)
2x^2+3x-8
2007-05-14 08:23:04 · answer #5 · answered by Anonymous · 2⤊ 0⤋
2x² + 3x - 8
2007-05-14 08:24:43 · answer #6 · answered by Como 7 · 1⤊ 0⤋
2x² + 3x - 8
remember to place a one in front of the second parethesis before distributing.
and why do u need to know this?
2007-05-14 08:29:01 · answer #7 · answered by c w 1 · 1⤊ 0⤋