How do you factorize?!
Like "x^2 + 6x + 5 =" and such.
I realize it should be in 2 sets of brackets, but how do you actually do it?
and how do you "factorize by completing the square?"
eg, "x^2 - 5x - 1 =" etc.
Thanks any help is appreciated ;)
Copyright © 2024 EBIN.TIPS - All rights reserved.
Answers & Comments
Verified answer
well i don't remember completing square method.but i wil tell u another way.
eg x^2 + 6x + 5 .here the constant term is 5,coefficient of x^2 term is 1,and that of x term is 6.
what u have to do is just think of two no such that product of those numbers is equal to the product of the const number and the coef of x^2 and thir sum is equal to the coef of x .here the product of constant and coef of x^2 is 5*1 which is 5.now convert x term that 6x to 5x+x .now just group x^2+5x+x+5
now (x^2+5x) + (x+5).now take x outside of 1st bracket and u get x(x+5) +(x+5). now taking x+5 common we get (X+5)(x+1).
another eg
in some eqn this won't work so use the quadratic eqn.
for a quadratic exp in the form ax^2+bx+c=0
it's roots are (-b +square root(b^2-4ac))/2a or -b -square root(b^2-4ac))/2a .
moreover if b^2-4ac is -ve then it has no real root.
x^2 - 5x - 1 =0
b^2-4ac = 25-4*-1 =29
therfore x= (5 +or -sqrt(29))/2 ie x=(5 +or - 5.38)/2 ie x=5.192 or -0.19.
if you want to learn how to factor it would help if you know how to do diamond problems. so for your example of x^2 + 6x + 5, just think 'what plus what equals 6 and what times what equals 5?' the sets of number that you add together to get 6 also have to multiply to 5. and since the variable is just a variable with no number next to it you dont have to worry about in this case. so, 5+1=6
and 5*1= 5, so, when factored it would look like this:
x^2 + 6x + 5 = (x+5)(x+1).
and about completing the square sorry i wasnt too good with that.
x^2+6x=-5
(x+3)^2=-5+9
(x+3)^2=4
x+3=+/- sqrt 4
x+3=+/- 2
x=3+/- 2
x=5, x=1
Move your five to other side, then factor your x^2+6x (make sure you add the 9 (3^2) to the other side since (x+3)(x+3)=x^2+6x+9 <----where the 9 comes from. Then solve for x.
x^2+6x+5=0
1*5=5 and 1+5=6
so we would use positive 1 and positive 5 to factor
and get
x^2+1x+5x+5=0
--> (x^2+x)+(5x+5)=0
-->x(x+1)+5(x+1)=0
--->(x+5)(x+1)=0
so x is -5 and -1
You factorize by this equation: a^2 + ab + ab