Question

Which equation is a quadratic equation?

3x − y = 8x + 2

y = 7x(5 − 2x) + 9

7x2 + y = (3 + x)(7x − 1)

y − 3 = (x2 − 3)(8x + 3)

Answer 1

Quadratic question: highest degree of polynomial is 2
For (1),
3x-y = 8x+2
y = -5x-2
the highest degree of polynomial is one .

For (2) , expand the expression.
y = 7x(5 − 2x) + 9
y = 35x - 14x^2 +9
= -14x^2 +35x +9
What is the highest degree of polynomial ?

For (3) , expand the expression.
7x^2 + y = (3 + x)(7x − 1)
7x^2 +y = 7x^2 + 21x - x -3
y = 20x -3
What is the highest degree of x ?

For (4), expand the expression.
y − 3 = (x^2 − 3)(8x + 3)
y - 3 = 8x^3 + 3x^2 - 24x -9
y = 8x^3 + 3x^2 - 24x - 6
What is the highest degree of polynomial ?

I think you can get the answer now~