Question

Which equation is a quadratic equation?

5x − 2 = y

y + 15x2 = (3x − 2)(5x + 7)

y = 3x(5 − x) + 7

y + 2 = (3x2 + 10)(x − 1)

Answer 1

an equation is quadratic when in standard form

y=a x^2
or

y=a x^2+b x

or
y=a x^2+b x +c

Answer 2

Or simply, anything in the "degree" (highest power) two with a \(y\) on the left side and \(x\)s on the right side.

Answer 3

Yeah, you convert them all such that you get something which looks like \(y = \cdots\).

Answer 4

isolate for y and they get in a standard form.

Solve for y

Answer 5

example a is already solved for y

5x − 2 = y

it isn't a quadratic cuss the x isn't squared

Answer 6

y = 3x(5 − x) + 7 is also solved for y but not in standard form

you need to distribute the 3x to 5 and - x do that and see what happens.

Answer 7

@HawkCrimson ... help please

Answer 8

ok :)

Answer 9

a quadratic function comes in the form y=a x^2+b x +c where a, b and c r just numbers.

so all quadratic functions much have x^2 in it, like look at the first equation 5x − 2 = y. does it have a x^2 in it?

Answer 10

no it doesnt

Answer 11

@HawkCrimson

Answer 12

so it's not a quadratic equation, now lets look at the second one y + 15x2 = (3x − 2)(5x + 7) expand it for me and tell me wat u get?

Answer 13

y = 11x - 14

Answer 14

so is it a quadratic equation?

Answer 15

no

Answer 16

gud now the 3rd equation y = 3x(5 − x) + 7 expand it, show me it and tell me if it is a quadratic equation

Answer 17

3(x - 5)x + y = 7

Answer 18

no it isnt?

Answer 19

u didnt expand it, u know how to?

Answer 20

no

Answer 21

y = 3x(5 − x) + 7 multiply 3x by everything in the brackets which r 5 and -x, do that and show me :)

Answer 22

15x and 3x^2

Answer 23

y = 15x − 3x^2 + 7 is it a quadratic formula?

Answer 24

yes

Answer 25

thank you! :)

Answer 26

ur welcome :)