Which equation is a quadratic equation?

y + 3 = 5x + 10

y + 4x2 = (4x − 2)(x + 3)

y − 8x = (x2 + 1)(9x − 7)

y = 2x + 7x(x + 1)

Question

Which equation is a quadratic equation? 

 y + 3 = 5x + 10 

 y + 4x2 = (4x − 2)(x + 3) 

 y − 8x = (x2 + 1)(9x − 7) 

 y = 2x + 7x(x + 1)

zpupster · Answer

$$a x^{2}+bx+c = 0$$

this is a quadratic equation , so we are to manipulate the given equations to find a 
equation that fits this definition.

can you do the first one

anonymous · Answer

is it B

zpupster · Answer

well lets try;
our zero here will be y so isolate y on one side
first lets mult the right hand side out
do oyu know the FOIL method

anonymous · Answer

yes i do @zpupster

anonymous · Answer

help me please

zpupster · Answer

sorry I had to leave it is not b because\
if we foil the right hand side:
we get 4x^2+10x - 6
subtracting the 4x^2 from both sides (we are getting rid of the right hand side 4x^2
to get the y by itself)
we are left:
y = 10x -6

that is not quadratic