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2007-02-10 19:14:43 · 8 answers · asked by Anonymous in Science & Mathematics Mathematics

8 answers

It's been about 12 years since I ever had to do this...but I think this is what you're trying to figure out:

x^2+x = 42
x^2+x-42 = 0
(x-6)(x+7) = 0, therefore
x=6, x=-7

2007-02-10 19:20:22 · answer #1 · answered by chrisatmudd 4 · 0 0

First: move the 42 to the Left Hand Side (LHS) It becomes X^2+X-42=0
then u prepare two brackets : ( ) ( )=0
fill in the bracket with (x + 7 ) (x - 6 ) =0
* x times x equals to x^2
7 times -6 equals to -42
the (first x times -6) + the (second x times 7) equals to x which is the same as the number in the center of the equation

Let (x+7)=0 (x-6)=0
then x = -7 x = 6

2007-02-11 04:24:34 · answer #2 · answered by simple_life726 1 · 0 0

first bring it in this form

x^2 + x - 42 = 0

take the coeff of x : +1

take the product of coeff of x^2 & constant : 1 * -42 = -42


now try to think of two numbers which when multiplied gives -42

& when added gives +1

-42 = -6 * 7
= 6 * -7
= 1 * -42
= -1 * 42
= 3 * -14
= -3 * 14
= 2 * -21
= -21 * 2

of all these possibilities only -6 , 7 will add to +1

so write the eqn as below

x^2 -6x + 7X -42

= x(x-6) +7(x-6)
=(x+7)(x-6)

2007-02-11 03:26:06 · answer #3 · answered by usp 2 · 0 0

x^2+x = 42
x^2+x-42 = 0
x^2+7x+6x-42 = 0
(x-6)(x+7) = 0, therefore
x=6, x=-7

2007-02-11 03:31:18 · answer #4 · answered by Krish 5 · 0 0

X^2+X=42
X^2+x-42=0
X^2+(7X-6X)+(+7*-6)=0 [Factors of -42 which differ by 1 are -6 and 7]
X(X+7)-6(X+7)=0
Answer is (X+7)(X-6)

2007-02-11 03:31:56 · answer #5 · answered by Govinda 3 · 0 0

x² + x - 42 = 0

(x + 7)(x - 6) = 0

x = -7, 6

2007-02-11 09:00:31 · answer #6 · answered by Como 7 · 0 0

x^2+x-42=0

(x+7) (x-6)

x+7=0 or x-6=0

x=(-7) or x=6

2007-02-11 03:23:09 · answer #7 · answered by Anonymous · 0 0

Subtract 42 from both sides. SO you have zero on one side. Apply the quadratic formula and Disco!

2007-02-11 03:18:10 · answer #8 · answered by alwaysmoose 7 · 0 0

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