What is the value of the coefficient "b" when the quadratic equation y = (3x − 5)(2x + 3) is written in standard form?

19

6

−15

−1

Question

What is the value of the coefficient "b" when the quadratic equation y = (3x − 5)(2x + 3) is written in standard form?

 19

 6

 −15

 −1

anonymous · Answer

do you know how to multiply this out?

anonymous · Answer

no can you help me

anonymous · Answer

you have to do 4 multiplications 
$$ (3x − 5)(2x + 3)$$
$$=3x\times 2x+3\times 3x-5\times 2x-5\times 3$$ is a start

anonymous · Answer

sometimes called "foil" by mediocre math teachers, but it is really the distributive law
we have more work to do

anonymous · Answer

$$=3x\times 2x+3\times 3x-5\times 2x-5\times 3=6x^2+9x-10x-15$$ then combine like terms and get 
$$6x^2-x-15$$

anonymous · Answer

now if we call 
$$6x^2-x-15$$ as $$ax^2+bx+c$$ we see that $a=6,b=-1,c=-15$

anonymous · Answer

ok

anonymous · Answer

all steps were there, hope they are clear 
i didn't skip any so you can look this over if you like

anonymous · Answer

so the answer is -15