[9.02] What are the solutions of x2 + 8x − 20 = 0? Show all work for full credit.

Question

cwrw238 · Answer

you need two numbers whose product is -20 and their sum = + 8

anonymous · Answer

4?

cwrw238 · Answer

no 2 numbers

anonymous · Answer

Oh, hold on let me think.

cwrw238 · Answer

factors wil look like  (x + a)(x - b)

waleed_imtiaz · Answer

x^2+8x-20=0
x^2+10x-2x-20=0
x(x+10)-2(x+10)=0
(x-2)(x+10)=0
So,,, x-2=0 and x+10=0...
x=2  and x=-10 .............................:)

anonymous · Answer

Thanks Waleed, But i'm trying to also figure out how to do it.
i'll read your response.

cwrw238 · Answer

do you see what the 2 numbers are Koqex?

anonymous · Answer

Yes, 10 and -2 .

cwrw238 · Answer

right

waleed_imtiaz · Answer

OKay.... My pleasure @Koqex ....

cwrw238 · Answer

you need not do it waleeds way once you have the 2 numbers just write
( x + 10)(x - 2) = 0

anonymous · Answer

Oh, that's it? i thought there would be more to this. haha.

cwrw238 · Answer

yes - do you see why solution s are -10 and 2?

waleed_imtiaz · Answer

Mm... U are right @cwrw238 ........

cwrw238 · Answer

theres less steps to do that way

anonymous · Answer

I'm trying to figure out how they are the solution, but i can't quite but my finger on it :\

waleed_imtiaz · Answer

@Koqex  the values of x=2,-10...... now  U can check if these values are in the solution set of the problem or not...... U just put the values one by one in the equation...... If u get the result equal on both sides, then ur answer is correct........