Question

Select all of the following that are quadratic equations.

Answer 1

5x ^2+ 15x = 0
3x ^2 + 5x - 7 = 0
x ^2 - 4x = 4x + 7

Answer 2

Answer:  First, Fourth, Sixth are correct options.

Step-by-step explanation:

Since we know that

Quadratic equation are those equations in which the highest degree should be 2.

So, According to this rule, we get that

$3x ^2 + 5x - 7=0\\\\x ^2 - 4x=4x + 7\\\\5x ^2+ 15x=0$

Hence, First, Fourth, Sixth are correct options.