Question

When the quadratic equation y = (x − 4)(2x + 5) is written in standard form, what is the value of the coefficient "b"?

Answer 1

do u know what the standard form is?

Answer 2

Not really ..

Answer 3

ok,here it is:
\[ax ^{2}+bx+c=0\]
can u try to put your given expression into this form??

Answer 4

its should be =y ...not =0

Answer 5

Let me try

Answer 6

I still haven't figured it out. Can you help me step by step ?

Answer 7

a. 2

b. 3

c. −3

d. −20

Answer 8

sure...
y=(x-4)(2x+5)
y=x*2x+5x-4*2x-5*4
y=2x^2+5x-8x-20
y=2x^2-3x-20
now compare this with
y=ax^2+bx+c
what u get as b??

Answer 9

-3 right ?

Answer 10

@hartnn

Answer 11

absolutely :)

Answer 12

Yay, thanks !!