Can someone please explain to me how to do problems like -3x(x^2+2) or (2x + 5) (x^2 - x - 2).
2007-09-17 06:48:55 · 5 answers · asked by hollister89 1 in Science & Mathematics ➔ Mathematics
Question 1
( -3x )( x ² + 2 ) = - 3 x ³ - 6 x
Question 2
( 2 x + 5 ) ( x ² - x - 2 )
2 x ³ - 2 x ² - 4 x + 5 x ² - 5 x - 10
2 x ³ + 3 x ² - 9 x - 10
2007-09-17 07:18:32 · answer #1 · answered by Como 7 · 2⤊ 1⤋
distribute -3x into the equation:
-3x^3 - 6x (which is counterproductive because you should factor out a 3x anyway)
to multiply 2x+5 and x^2 - x - 2 you can use the foil method... or the method I use which is long multiplication (line up like terms and multiply as if you were multiplying a large number such as 250 x 40):
x^2 - x - 2
2x + 5
________
5x^2 -5x-10
2x^3 -2x^2-4x +0
______________
2x^3+3x^2 -9x -10
2007-09-17 07:04:20 · answer #2 · answered by Lollipop 5 · 0⤊ 2⤋
-3x(x^2+2) = -3x^3 - 6x
(2x+5) (x^2-x-2) = 2x^3 - 2x^2 - 4x + 5x^2 -5x-10
=
2x^3 + 3x^2 -9x - 10
2007-09-17 07:00:12 · answer #3 · answered by Anonymous · 0⤊ 2⤋
Let me show that will show to do other one
(2x+5)(x^2-x-2)
=2x(x^2-x-2)+5(x^2-x-2)
or 2x^3-2x^2-4x+5x^2-5x-10
or 2x^3+3x^2-9x-10 ans
2007-09-17 07:09:20 · answer #4 · answered by MAHAANIM07 4 · 0⤊ 2⤋
-3x(x^2+2)=-3x*x^2-3x*+2=-3x^3-6x
(2x + 5) (x^2 - x - 2)=2x(x^2-x-2)+5(x^2-x-2)
=2x^3-2x^2-4x+5x^2-5x-10
=2x^3+3x^2-9x-10
2007-09-17 07:24:48 · answer #5 · answered by Anonymous · 0⤊ 3⤋