Find the solutions to the equation: x^2 + 2x – 8 = 0.?

Question

a. x=-4,2
b. x=-3,5
c. x=-2,4
d. x=4,4

Answer 1

(x + 4)(x - 2) = 0
Answer (a).

Answer 2

The answer is A

X^2+2X-8=0

1.You automatically put this...
(X ) (X )=0

2. Then, to know the signs you need to look at the sign the last number in the equation has (this case is -8, that means the signs are different, one + and one -)
(X+ ) (X- )=0

3. Now since the number in the middle that multiples the X is positive (in this case 2X, you know that the parenthesis that has the plus has the biggest number)
(X+4)(X-2)=0

You obtain this 4 and -2 because this numbers are the ones that give you a 2 when added, and a -8 when you multiply it.

Just remember now to change the signs!!!

Got it???.....

Answer 3

the solutions to the equation are going to be factors of -8
they are also going to add up to 2

based on this, you can eliminate b and d
a is the answer

the other way to do this would be to factor the equation

the solutions to the equation are going to be factors of -8
they are also going to add up to 2

(x + ___)(x + ___) ~> (x + 4)(x + -2)
then use the zero product property and solve for x
(x + 4)(x + -2) = 0, therefore one term must = 0
(x + 4) = 0, x = -4
(x + -2) = 0, x = 2

Answer 4

x^2 + 2x - 8 = 0
( x + 4 ) ( x - 2 ) = 0
x + 4 = 0
x= -4

or

x - 2 = 0
x = 2

Answer 5

I see that no-one actually reads the question before rushing to answer it. Since you are given that y = x² - etc, I presume that you are meant to draw the graph and note where the graph crosses the x-axis (particularly since you are told not to solve the equation.) You will have to draw the graph for yourself. Just note the points where it crosses the x-axis. (you have already been told which points these are, so it should not be difficult.)

Answer 6

quadratic equations have two solutions in general.

let the solutions be x=a and x=b

then (x-a) (x-b) = 0
or x^2-(a+b)x +ab = 0

a+b = ? ab = ?

then, a = ? and b = ?

exercise your brain a bit and get the answers.

That would make you a good learner !!

Answer 7

x^2+2x-8=0
or x^2-2x+4x-8=0
or x(x-2)+4(x-2)=0
or (x-2)(x+4)=0
so x=2 or x=-4 i.e.,(a) ans

Answer 8

(x+4)(x-2)
x=-4, x=2 <------- you're finding the zeros so the answer is a

Answer 9

-4^2=16
16-8-8=0....

-2^2=4
4+4-8=0....
the answer is a........

Answer 10

(x + 4) (x - 2) = 0
x = - 4 , x = 2
OPTION a.