Question

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

7

−7

2

−15

Answer 1

so, use FOIL technique to expand out the brackets
then pick your answer, knowing that y = ax^2 + bx + c

Answer 2

do you understand FOIL technique...?

Answer 3

To find the answer we can write :
\[(x-5)(2x+3)=2x^2+3x-10x-15=2x^2-7x-15\]
Then :
\[a=2~~b=-7~~~c=-15\]