EASY question (1 Viewer)

[smellyshitboy]

i forgot how to do these and can't find them in either of my books. HOW DO YOU SOLVE THESE?

2x²+5x-3

 

[tommykins]

Quadratic formula.

-b(+-)sqrt(b²-4ac)
-----------------------
2a

In this case - a = 2, b = 5, c = -3

 

[wendus]

or you can use the cross method to obtain the same result.

 

[Troy2287]

<3 Quadratic formula..

 

[smellyshitboy]

wait i meant to say factorize how do you factorize it

 

[tommykins]

use quadratic formula and obtain yuor x values and then factorise.

for example if the quadratic formula gives the answers -3 and 5/4, if you were to factorise it, it becomes (x+3)(4x-5) = 0

same thing applies to this function.

 

[wendus]

lolll

to factorise you go 'what two values of x multiply to give -3 and add up to give 5?'

and that's your answer.

 

[tommykins]

lolll

to factorise you go 'what two values of x multiply to give -3 and add up to give 5?'

and that's your answer.

No, a = 2.

 

[kaz1]

i forgot how to do these and can't find them in either of my books. HOW DO YOU SOLVE THESE?

2x²+5x-3

2x²+5x-3=0
To factorise
2x²+6x-x-3=0
2x(x+3) -1(x+3)=0
(2x-1)(x+3)=0
x=0.5,-3

 

[DownInFlames]

(2x ) (x )

do these ones ^^^^

then you know from the -3 that you need 1 and 3 in there, and on of them has to be negative:

(2x - 1) (x + 3) = f(x)


this just skips the in-between steps.