i dont get this?

Question

multiply.

(x/3+3/4)(3x/4-3/5)

Answer 1

Change the question

( (1/3)x+3/4 ) ( ( 3/4)x - 3/5 )

Shall we get rid of fractions....

Lets consider

[ 12* ( (1/3)x+3/4 ) * 20* ( ( 3/4)x - 3/5 ) ] * (1/240)

12*20 gives us 240. Since we multiplied by 240 we will divide by 240

Multiplying
( (12/3)x+36/4 ) * ( (60/4)x-60/5 ) * 1/240

(4x+9)(15x-12) * 1/240

Now FOIL

(60x^2-48x+135x - 108) * 1/240

(60x^2+87x-108)* 1/240

put the fraction in

(60/240) x ^2 + (87/240) x - 108/240

simplify

(1/4) x^2 + 87/240 x - 9/20

Answer 2

It might help you to sort out the fractions:
this is the same as
((1/3)x+(3/4)) times ((3/4)x+(-3/5))
now:
FOIL
First:
(1/3)x*(3/4)x =(1/4)x^2
Outside:
(1/3)x*(-3/5)=(-1/5)x
Inside:
(3/4)*(3/4)x=(9/16)x
Last:
(3/4)*(-3/5)=-9/20
All together:
(1/4)x^2+(-1/5)x+(9/16)x+(-9/20)
Using the Least Common Denominator for (-1/5)and(9/16) which is 80
(1/4)x^2+(-16/80)x+(45/80)x+(-9/20)
=(1/4)x^2+(29/80)x-(9/20)
that can also be written as:
(x^2)/4 + (29x)/80 -9/20
That's it!

Answer 3

Use FOIL (First, Outside, Inside, Last):

F: x/3 * 3x/4
O: x/3 * 3/5
I: 3/4 * 3x/4
L: 3/4 * 3/5

x/3 * 3x/4 = (3x^2)/12 = (x^2)/4
x/3 * 3/5 = x/5
3/4 * 3x/4 = 9x/16
3/4 * 3/5 = 9/20

(x^2)/4 + x/5 + 9x/16 + 9/20
1/4x^2 + 16x/80 + 45x/80 + 9/20
1/4x^2 + 61x/80 + 9/20

Answer 4

Hi,

(x/3+3/4)(3x/4-3/5) =

¼x² - 1/5x + 9/16x - 9/20 =

¼x² + 29/80x - 9/20

I hope that helps!! :-)

Answer 5

(x/3+3/4)(3x/4-3/5)
(x/3)(3x/4) + (x/3)(-3/5) + (3/4)(3x/4) + (3/4)(-3/5)
3x^2/12 - 3x/15 + 9x/16 - 9/20
x^2/4 - 48x/240 + 135x/240 - 9/20
x^2/4 + 87x/240 - 9/20
x^2/4 + 29x/80 - 9/20

Answer 6

use foil.

3(x^2)/12 - 3x/15 + 9x/16 - 9/20
=(x^2)/4 +87/240x - 9/20
=1/4(x^2)+29/240x - 9/20

Answer 7

use the FOIL method