Find the best solutions to your problems with the help of IDNLearn.com's experts. Get timely and accurate answers to your questions from our dedicated community of experts who are here to help you.

2x^2-3x-9 please help

Sagot :

Im assuming you mean 2x^2-3x-9=0 ?
If so, you have to factorise the equation
(2x-3) (x+3) = 0

2x - 3 = 0
2x = 3
x = 1.5

x + 3 = 0
x = -3

x is either 1.5 or -3

so  factor

if you have ax^2+bx+c then to factor find
x+y=b
xy=ac
so

a=2
b-03
c=-9
2 times -9=-18

factor -18
-1,18
-2, 9
-3, 6


now add and find the one that adds to -3


-1+18=17
-2+9=7
-3+ 6=3, could work, if signs are reversed

so the numbers are -6 and 3

split -3 up
2x^2-6x+3x-9
group
(2x^2-6x)+(3x-9)
undistribute
(2x)(x-3)+(3)(x-3)
reverse distributive property
ab+ac=a(b+c)
(2x+3)(x-3)


so we can't do anything else because it isn't an equation so it has non meaning

if it does equal zero then
xy=0 then x and/or y=0 so

(2x+3)(x-3)=0 so
2x+3=0 and x-3=0 so

2x+3=0
subtract 3 from both sides
2x=-3
divide by 2
x=-1.5

x-3=0
add 3 to both sides
x=3



x=-1.5 or 3