Question

Help!!
Find the factor form for: f(x)= 4x^2-24x+35

Answer 1

not facorable, must use quadratic

Answer 2

It's actually factorable. (2x-7)(2x-5)

Answer 3

The thing to do is multiply a & c first: 4 * 35 = 140
The middle term b is negative and the product ac is positive.
So be should be split into two negatives whose sum is -24 and their product is 140
-24 split into -14 and -10 will do the job.

Answer 4

Thanks ^.^ for the help, you guys! I get it now!

Answer 5

missed it, sorry

Answer 6

@ranga Ins't that the box and diamond method?

Answer 7

Isn't*

Answer 8

I don't know the name for it but that is what I do.
-24 can be split as -23 -1 or -22 -2, -21 -3, and their product is getting higher but not fast enough to reach 140. So skip a few numbers and go with -18 - 6, -17 -7, etc and soon you will know if it is factorable or not.

Answer 9

great tip ranga, I found the answers enough quick before posting but after I convinced myself it wasn't factorable

Answer 10

thanks ehuman.

Answer 11

@Deli-chan
you CAN use the diamond and box method. it will also work

Answer 12

can you elaborate on that method @nikato?

Answer 13

@nikato I'm still learning the method!! >.<

Answer 14

ok then. you see how ur equation is writeen in the form
y=Ax^2 +Bx +C

Answer 15

I have also seen it called the "Xbox method." Presumably because naming it after something that students probably like somehow makes it more interesting. I don't think this works at all.

Answer 16

so in the picture the top number is what you get when you multiply A and C
and the bottom number is just B