A quadratic equation is one in which the highest exponent of x is 2.

is quadratic; the highest exponent is 2.
x³-3x²+1=0 is NOT quadratic. The highest exponent of x is 3, not 2.
5x-7=0 is NOT quadratic. The highest exponent of x is 1, not 2.
x²+3x-5=0 is quadratic; the highest exponent of x is 2.
x-5=9x+7 is NOT quadratic. The highest exponent of x is 1, not 2.
x²-x=3x+7 is quadratic; the highest exponent of x is 2.
Answer:
(18, ∞)
Step-by-step explanation:
(18, ∞) is the only option that works. if we ignore the "greater than" sign, and just set the function equal to -12, we see that x-10=-12 would give us x=-2. If we plug in -3 for x, we get -13, which is less than -12. if we plug in -1 for x, we get -11, which is greater than -12. Therefore, with the function only having one critical point (zero), we know that every value greater than -2 is a solution. Technically, the full solution would be (-2, ∞). however, the only answer available meeting the criteria would be (18, ∞).
No on can explain it but it has a definition.