Can you help me with these three questions?

1.Identify which equation is a quadratic equation.
y = −6x − 3
y + x2 = (x − 1)(x + 7)
y − 9 = (x − 1)(x2 + 4)
y = 5x(x + 3) − 8

2.What are the solutions of 6x2 + 7x – 5 = 0?

3.Solve 3x2 = 12x.

Question

Can you help me with these three questions?


1.Identify which equation is a quadratic equation.
 y = −6x − 3
 y + x2 = (x − 1)(x + 7)
 y − 9 = (x − 1)(x2 + 4)
 y = 5x(x + 3) − 8

2.What are the solutions of 6x2 + 7x – 5 = 0?

3.Solve 3x2 = 12x.

anonymous · Answer

I think 3 is  x = 0, x = 4 but I'm not sure.

mandre · Answer

Yes for 3

A quadratic equation is where the maximum power is 2. So simplify each equation to determine which is quadratic.

anonymous · Answer

^^^ Sorry I'm still not understanding what is a maximum power and where would that be? @Mandre Thanks!

mandre · Answer

In the following equation:
x^4 + x^2 + x -20
the maximum power would be 4 because we have x^4

You understand?

anonymous · Answer

So would D, be the answer since the largest power is two?

mandre · Answer

What about B?

anonymous · Answer

C would be a maximum of three, right? So that couldn't be it.

anonymous · Answer

B could work because there is a maximum power of 2 but there are a lot to the power of two.

mandre · Answer

A and C is definitely not.

anonymous · Answer

I agree with that.

mandre · Answer

does not matter how many there are. You can add or subtract to make it one.

mandre · Answer

Can you pick more than one answer?

anonymous · Answer

No.

mandre · Answer

Then there is a problem. Both B and D are quadratic unless you typed it wrong.

anonymous · Answer

attachment

anonymous · Answer

Thats how they should look.

mandre · Answer

Haha. Look at B again. Bring all terms to the left then you see what the problem is

anonymous · Answer

Yes, so what do you suggest I do. Lol

mandre · Answer

What happens to the x^2 if you bring all terms to the left once you've multiplied on the right?

anonymous · Answer

It would cancel out.

anonymous · Answer

Wait, no it won't let me try doing it again.

anonymous · Answer

I don't think I'm doing it right, everything is on one side equal to 0.

mandre · Answer

y + x2 = (x − 1)(x + 7)
y + x2 = x2 +7x -x -7

anonymous · Answer

The x^2 would cancel out if I moved it over.

mandre · Answer

Yup. So problem solved right?

anonymous · Answer

So would D be the answer?

mandre · Answer

Yes.

anonymous · Answer

Okay that makes a lot more sense. Thank you for helping me you don't even know how much that helped me out I've been struggling with that problem for the past hour. Thanks for your time I really appreciate it!

mandre · Answer

My pleasure.