QUADRATIC FORM AND SOLVE BY FACTORING 9x(x-7) = -90?

9x*x – 9x*7 = -90

which gives us

9x^2 – 63x = -90

which becomes a quadratic formula

9x^2 – 63x + 90 = -90 + 90

9x^2 – 63x + 90 = 0

since 1 and 9 are factors of 9 and 2 and 45 are factors of 90, by trial and error, we can find that the simplification is this:

(x – 2)(9x – 45)

which can be rechecked by factoring:

9x*x – 45*x – 2*9x – 2*-45 which becomes

9x^2 – 45x -18x -90 or 9x^2 – 63x -90

since it checks, (x – 2)(9x – 45) is correct

If, however, you want to simplify your quadratic formula first, you have

9x^2 – 63x = -90

9(x^2-7x-10)=0

which is

9(x-2)(x-5)

either one works

9x^2-63x+90 = 0

all terms have a factor of 9

9 ( x^2 -7x + 10) = 0

what 2 numbers add to -7 (a+b = -7), and when multiplied give 10 (ab = 10).

i will let you get those numbers…..

so 9(x-a)(x-b) = 0

either (x-a)=0 or (x-b) = 0

so, roots (solution) is: x=a, x=b

g.l.

9x^2 – 63x + 90 = 0 set to 0

divide by 9

x^2-7x+10

(x-5)(x-2)