How do you know if an equation is linear, quadratic or exponential?

Y=3X^2+4X-4

Y=2(4)^X

y=3X+2

Those equations are examples. If someone could tell me the rule for knowing if it's linear, quadratic or exponential, i would appreciate it.

2. Is linear if the highest order exponent is 1. This is given no exponents are fractional or negative. Your 3rd example is linear.

$y = 3x+2 = 3x^1+2$

Is quadratic if the highest order exponent is 2. This is given no exponents are fractional or negative. Your 1st example is linear.

the 2nd is exponential as the unknown is in the exponent.

3. Thanks....