Algebra 2 help, please?

here:

(x+11)(x-6)

because -6*11=-66 and 11-6=5

x=-11 x=6

x-2x=8

then square 2 and divide by 2

2/2

x-2x +2 = 8+2

(x-1)^2 = 10

and finally

(x-(-6)(x-3)

(x+6)(x-3)

then multiply

x^2+6x-3x-18

x^2+3x-18

x^2 + 5x - 66 = 0

(x + 11)(x - 6) = 0

x = -11 or x = 6

x^2 - 2x - 8 = 0

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

x = 4 or x = -2

-6 and 3 are roots

x = -6 or x = 3

x + 6 = 0 or x - 3 = 0

(x + 6)(x - 3) = 0

now expand

x^2 + 3x - 18 = 0

the first one:

x^2 + 5x - 66 =0

it's already equal to zero, so you can skip that step.

the second sign is negative, so you know your signs of answers will be different.

the factors of 66 are (1,66) (2,33) (3,22) (6,11)

11-6 = 5

so...

your factors are

(x+11) (x-6)

now set both equal to zero

x+11=0 x-6=0

x=-11 x=6

i don't remember completing the square, sorry.

third one.

you've been given the roots.

so work backwards.

x=-6 x=3

x+6 =0 x-3=0

(x+6)(x-3)=0

x^2 -3x+6x-18=0

x^2+3x-18=0

Ooh! Snacks!

I'll try that yummy third problem!

For the roots negative six and three, the factors are

(x + 6) and (x - 3)

Multiply them together to get the quadratic equation:

x² + 3x - 18 = 0

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