Im so ashamed to be asking this easy question - Quadratics (factorising).?

Question

Now, before I begin I must stress that I can do basic quadratics and i'm not an idiot. I just can't believe that the teacher did a typo.

The question is to factorise:
x^2 + 7x -10

Easy, right?

Is this an incorrect question or am I just being incredibly obtuse?
Many thanks and apoligies for my idiocy.

Answer 1

Doesn't work



it would be (x+2)(x+5)

IF

it was x^2 + 7x + 10



SORRY!

x

Answer 2

You need to find two numbers that multiply to -10 and add to 7.



The factors of -10 are

1, -10

2, -5

5, -2

10, -1



Adding them together give you

-9

-3

3

9

respectively



None of which are 7. So either the signs should be switched (multiply to 10 and add to -7, which would be -2, -5) or there is something else wrong with the question (missing coefficient on x^2, etc)



So yes, as it is, the only factorization is the question itself. It can not be factored



(this isn't entirely true, using advanced methods you can factor it into -1/4(-2x + sqrt(89) -7)(2x + sqrt(89) + 7) but I doubt this is what you're looking for)



Cheers

Answer 3

i visit assist you already know the final type for factorizing quadratics. right here you have it: enable a quadratic be: ax² + bx + c, with a ? 0 First you detect the roots x_1 and x_2 of the equation ax² + bx + c = 0, utilising the quadratic formula. We call discriminant the selection: D = b² - 4ac. If D < 0 then the quadratic won't be able to be factorized. If D = 0, than the quadratic turns into factorized: ax² + bx + c = a(x + b/2a)² If D > 0 then: x_1 = (-b+?D)/2a, x_2 = (-b-?D)/2a and the quadratic turns into: ax² + bx + c = a(x - x_1)(x - x_2) desire that enables!

Answer 4

I think you need to go back to primary school. You have to understand that 1+1=2 and not equal to 98, because Obama will kiss you if you insist.



goodluck!