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Mathematics 7 Online
OpenStudy (anonymous):

x ^2 - 12 = 5x + 2

OpenStudy (anonymous):

you need to solve for x?

OpenStudy (anonymous):

x^2-5x=14

OpenStudy (charlotte123):

x^2 = 5x + 14.

OpenStudy (anonymous):

x^(2)-12=5x+2 Since 5x contains the variable to solve for, move it to the left-hand side of the equation by subtracting 5x from both sides. x^(2)-12-5x=2 Move all terms not containing x to the right-hand side of the equation. x^(2)-5x-12=2 To set the left-hand side of the equation equal to 0, move all the expressions to the left-hand side. x^(2)-5x-14=0 In this problem 2*-7=-14 and 2-7=-5, so insert 2 as the right hand term of one factor and -7 as the right-hand term of the other factor. (x+2)(x-7)=0 Set each of the factors of the left-hand side of the equation equal to 0. x+2=0_x-7=0 Since 2 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 2 from both sides. x=-2_x-7=0 Set each of the factors of the left-hand side of the equation equal to 0. x=-2_x-7=0 Since -7 does not contain the variable to solve for, move it to the right-hand side of the equation by adding 7 to both sides. x=-2_x=7 The complete solution is the set of the individual solutions. x=-2,7

OpenStudy (anonymous):

the underscores are just spaces

OpenStudy (primeralph):

@thewonderfuladele That's really elaborate.

OpenStudy (charlotte123):

x^2 + -12 = 5x + 2 ----> -12 + x^2 = 5x + 2 ----> -12 + x^2 = 2 + 5x. -12 + -2 + -5x + x^2 = 2 + 5x + -2 + -5x -----> -12 + -2 = -14 -14 + -5x + x^2 = 2 + 5x + -2 + -5x -----> -14 + -5x + x^2 = 2 + -2 + 5x + -5x. 2 + -2 = 0 ----> -14 + -5x + x^2 = 0 + 5x + -5x ----> -14 + -5x + x^2 = 5x + -5x. 5x + -5x = 0 ----> -14 + -5x + x^2 = 0. (-2 + -1x)(7 + -1x) = 0 <---- -2 + -1x = 0 -2 + -1x = 0 -2 + 2 + -1x = 0 + 2 2 + 2 = 0 0 + -1x = 0 + 2 ----> -1x = 0 + 2 0 + 2 = 2 ----> -1x = 2 x = -2

OpenStudy (charlotte123):

Then - 7 + -1x = 0 7 + -7 + -1x = 0 + -7 ----> 7 + -7 = 0 ----> 0 + -1x = 0 + -7 -----> -1x = 0 + -7. 0 + -7 = -7 ----> -1x = -7. x = 7

OpenStudy (charlotte123):

Thus - x = -2. x = 7.

OpenStudy (anonymous):

WAIT WAIT WAIT GUYS LOOK

OpenStudy (charlotte123):

WHAT

OpenStudy (anonymous):

hmm?

OpenStudy (anonymous):

x^2-5x-14 ok?

OpenStudy (anonymous):

factor it so (x-7)(x+2) x=7; -2

OpenStudy (charlotte123):

Oh wow LOL

OpenStudy (anonymous):

Yeah haha it just clicked. SO yeah thats SOOOOOOOOOOO much easier, right? and it makes sense?

OpenStudy (charlotte123):

YES

OpenStudy (charlotte123):

Clean - Easy - Wow

OpenStudy (anonymous):

whydidinotseethatbefore. the only question left isss does @JoStudy get it? get how I factores it

OpenStudy (primeralph):

Yeah, it's easy. It's just best to elaborate so people see the inner works. Good job.

OpenStudy (anonymous):

Thanks everybody! And can you explain thaht @klakelyn ?

OpenStudy (charlotte123):

No problem!

OpenStudy (anonymous):

sure hang on @JoStudy

OpenStudy (anonymous):

since you have x^2-5x-14 you need to factor it to factor it you need to find 2 values that multiply together to get -14, and when they are added you get -5.

OpenStudy (anonymous):

so the factors of -14 are 1,-14 or -1,14 or 2,-7 or -2,7

OpenStudy (anonymous):

-7 and 2 multiply out to get -14 and add together to get -5. when you get your factor as (x-7)(x+2) you multiply it out to check your work use F(irst)O(uter)I(nner)L(ast) FOIL so

OpenStudy (anonymous):

@JoStudy x^2+2x-7x-14 x^2-5x-14 does that make sense?

OpenStudy (anonymous):

Thanks!

OpenStudy (anonymous):

No probs:)

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