i just cant wrap my head around it

factor

x^2-10x+21

Question

i just cant wrap my head around it

factor

x^2-10x+21

anonymous · Answer

7 and 3!

jim_thompson5910 · Answer

Find two numbers that multiply to 21 AND add to -10: These numbers are -7 and -3

x^2-10x+21

x^2-7x-3x+21

x(x-7)-3(x-7)

(x-7)(x-3)


So x^2-10x+21 = (x-7)(x-3)

anonymous · Answer

lol my first thoughts were 7 and 3 too XD

saifoo.khan · Answer

$$\Huge (x-3)(x-7)$$

anonymous · Answer

ohhhhhhhh!!!!!! two negatives make a positive thanks guys

anonymous · Answer

what is that cool way that they teach nowadays where the leading and last coefficient = yada yada... i never use that way

anonymous · Answer

x^2-10x+21
x^2-7x-3x+21
(x-7)(x-3)

anonymous · Answer

leading and last are only for problems with a coefficent on the first x

anonymous · Answer

oh hahaha i never use it so i wouldn't know haha

anonymous · Answer

like 7x^2+5x+30 or something. factors of 7 and factors of 30

anonymous · Answer

4y^2_49????

anonymous · Answer

*-

jim_thompson5910 · Answer

4y^2-49 = (2y+7)(2y-7) using the difference of squares rule.