how do you multiply out (3x-1)(4x+2)?

2010-01-08 2:02 pm

回答 (12)

2010-01-08 2:09 pm
✔ 最佳答案
(3x - 1)(4x + 2) Use FOIL method.

F means multiply the First terms in each binomial. 3x(4x) = 12x^2.

O means multiply the two Outer terms in each: 3x(2) = 6x.

I means mutltiply the two Inner terms in each: (-1)(4x) = - 4x.

L means multiply the Last terms in each: (-1)(2) = - 2.

Put them together: 12x^2 + 6x - 4x - 2. Combine the x terms.

12x^2 + 2x - 2. Answer.
參考: Self
2016-05-26 2:58 pm
3x√2 multiplication with √14x = 3√28x^2 = 6√7 x^2 I am taking x out of the square root in both the cases.
2010-01-08 7:09 pm
12 x ² + 6 x - 4 x - 2

12 x ² + 2 x - 2
2010-01-08 2:35 pm
(3x- 1)(4x + 2 )
= 3x.4x + 2.3x – 4x – 2
= 12x² + 2x – 2
You do some on line too long
2010-01-08 2:26 pm
(3x - 1)(4x + 2)
= 3x(4x) + 3x(2) - 1(4x) - 1(2)
= 12x^2 + 6x - 4x - 2
= 12x^2 + 2x - 2
2010-01-08 2:21 pm
(3x - 1 )(4x + 2 ) = [ ( 3x * 4x )+ 6x ] - [ 4x - 2 ] = 12x² + 6x - 4x - 2 = 12 x² + 2x - 2

^^
參考: My sources!
2010-01-08 2:11 pm
The (3X - 1) is saying multiply the other side by that, split up the left hand side, so you can re-write the equation as:

3X (4X + 2) - 1 (4X + 2)

Now split up the (4X + 2) bits to give:

3X x 4X + 3X x 2 - 1 x 4X - 1 x 2 - remember to get all the + and - correct

Which is:
12X^2 +6X - 4X - 2

Which you can add together to give:
12x^2 + 2x -2
2010-01-08 2:11 pm
(3x-1)(4x+2) =
12x^2 + 6x - 4x - 2 =
12x^2 + 2x - 2
參考: maths
2010-01-08 2:10 pm
You will go by the terms:

3x*4x + 3x*2 -1*4x -1*2 = 12x^2 + 6x - 4x - 2 = 12x^2 + 2x - 2
2010-01-08 2:09 pm
(a + b)(c + d) = ac + ad + bc + bd
Specifically, (3x - 1)(4x + 2) = 3x(4x) + 3x(2) - 1(4x) - 1(2) =
12x^2 + 6x - 4x - 2 =
12x^2 + 2x - 2


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