Simple algebra problem that i don't get?

Question

how do you find "a" and "b" here?

(x+a)(x+6)=x^2+bx-20

Answer 1

multiply out the brackets on the left to get

x^2 + (6 + a)x + 6a = x^2 + bx - 20

then take each power of x and equate its factor

1 x^2 = x^2

x => 6 + a = b

x^0 => 6a = -20 => a = -20/6 = -10/3

therefore 6 - 10/3 = b = 8/3

Answer 2

it cant be solved

Answer 3

(x+a)(x+6) = x² + bx - 20

For the equations to be equal, a*6 has to equal negative 20.

a*6 = -20

a = -20/6

a = -10/3

(x² - 10/3x + 6x - 20) = x² + bx - 20

x² - 10/3x + 18/3x - 20 = x² + bx - 20

x² + 8/3x -20 = x² + bx -20

So now we know that b is equal to 8/3.

a = -3,3333333...

b = 2,6666666...

Answer 4

it can't be solved

Answer 5

Let's FOIL the left side and see what we get..

x^2 + 6x + ax + 6a = x^2 + bx - 20

x^2 + (6x + ax) + 6a = x^2 + bx - 20

Then (6x + ax) = bx ... and ....6a = - 20

Let's solve 6a = - 20

a = - 20/6 or - 10/3

Then (6x + ax) must equal (6x + -3.33333x)  = bx

(8/3) x = b x

so b = 8/3  or 2.6666666666666

Good luck to you !!

Answer 6

you can't. You have one equation with 3 unknowns, and it cannot be solved.

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