Question

Please help

Use the quadratic model y = -4x^2-3x +4 predict y if x equals 5

a.-111
b.-89
c.-51
d.-411

Answer 1

So everywhere you see an x just place a 5 there and calculate it out.

Answer 2

I got -411 is that correct @Kainui ?

Answer 3

Nope, so try doing each term individually and tell me what they are, then add them together.

-4x^2

-3x

4

Answer 4

the first on is -20 then -15 then 20

Answer 5

@Kainui

Answer 6

The first term is -4 times 5^2 not 5. Don't forget to square it!

Answer 7

yeah 4 x 5 is 20

Answer 8

-20^2 is 400

Answer 9

@Kainui

Answer 10

Nope, you have to square it first then multiply after, not the other way around. That's just the rules.

Answer 11

well thats 80

Answer 12

-4 * 25 is not 80, try again.

Answer 13

-100

Answer 14

got it, now just add them all up and you should be good.

Answer 15

so -100 + (-15) + 20

Answer 16

Not quite.

Answer 17

\(y = -4x^2-3x +4\) Only plug in a 5 where there is an x.

Answer 18

\(-4x^2 = -4(5^2) = -100\) That's correct.
\(-3x = -3(5) = -15\) That's correct.
What's left?

Answer 19

4 is left @gypsy1274

Answer 20

OK. so add them all together.

Answer 21

I got -111

Answer 22

Yes.

Answer 23

thank you all

Answer 24

Your welcome.