what does x equal to in this equation x^2-20x-96=0?

2008-12-16 2:28 pm
aslo solve for x
1) ax+2=bx+c
2) x/c+c= 4c
3) ax-bx=2a

please i need help in exams !
更新1:

how did you get 24 and -4 where did those numbers come from

回答 (5)

2008-12-16 2:32 pm
✔ 最佳答案
x² - 20x - 96 = 0
(x - 24)(x + 4) = 0
If x-24 = 0, x = 24
If x + 4 = 0, x = -4

Thus, x = 24 or x = -4
====================

1) ax+2=bx+c
ax - bx = c - 2
x(a - b) = c - 2
x = (c - 2) / (a - b)

2) x/c+c= 4c
x + c² = 4c²
x = 3c²

3) ax-bx=2a
x(a - b) = 2a
x = 2a/(a - b)
2008-12-16 11:07 pm
1)
x^2 - 20x - 96 = 0
x^2 + 4x - 24x - 96 = 0
(x^2 + 4x) - (24x + 96) = 0
x(x + 4) - 24(x + 4) = 0
(x + 4)(x - 24) = 0

x + 4 = 0
x = -4

x - 24 = 0
x = 24

∴ x = -4 , 24

= = = = = = = =

2)
ax + 2 = bx + c
ax - bx = -2 + c
x(a - b) = c - 2
x = (c - 2)/(a - b)

= = = = = = = =

3)
x/c + c = 4c
x/c = 4c - c
x = c(3c)
x = 3c^2

= = = = = = = =

4)
ax - bx = 2a
x(a - b) = 2a
x = 2a/(a - b)
2008-12-16 10:46 pm
their sum is the coefficient of x and their product is the constant.
2008-12-16 10:41 pm
x^2-20x-96=0 we have two solutions : x1 = 8 and x2 = 12
2008-12-16 10:35 pm
first, factor (x-24)(x+4)=0, set each factor = 0
x-24=0 or x+4=0 so x = 24 or x = -4

1. ax-bx=c-2 factor out x
x(a-b)=c-2 divide by a-b
x=(c-2)/(a-b)

2. x/c=3c multiply by c both sides
x=3c^2

3. factor out x x(a-b)=2a
divide by (a-b) x=2a/(a-b)


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