Help with algebra equation
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Help with algebra equation

[From: ] [author: ] [Date: 11-08-25] [Hit: ]
b - 5 = 0orb + 4 = 0. b = 5 or -4.-You have to factor it into product of binomials.Factors of -20 that add to -1 are -5 and 4 so,......
the question says solve by factoring, and the equation is b^2-b-20=0, with b being a variable and the ^2 meaning squared. i already factored the equation (i think) fully or half way, with my answer being -20+b(b-1)=0. what do I do from here, also did i factor correctly?

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When factoring quadratic equations, (which is what you have here), you usually want to put it in this form,

(b + x)(b + y).

For your problem, you need to find an x and y such that

x + y = -1 (coefficient in front of b)
x * y = -20. (number with no variable)

x = -5 and y = 4 will work. So you will have the factored form,

b^2 - b - 20 = (b - 5)(b + 4).

Now since the original equation equals zero you have,

(b - 5)(b + 4) = 0.

When you multiply two numbers together and the answer is zero then at least one of the two numbers must be zero. Therefore we can say

b - 5 = 0 or b + 4 = 0.

Then solve for b id both cases and you get

b = 5 or -4.

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You have to factor it into product of binomials.

Factors of -20 that add to -1 are -5 and 4 so,

b^2 - b - 20 = 0 iff
(b - 5)(b + 4) = 0 [zero product property] iff
b - 5 = 0 or b + 4 = 0 iff
b = 5 or b = -4
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