Question

what is the difference between a linear function and a quadratic function

Answer 1

Linear means the highest power in the equation is 1. Itll be a straight line. Quadratic means the highest power in the problem is 2, itll be a parabola shape.

Answer 2

Highest power of the variable I mean

linear:
y = 4x - 5
y = x
x + y = 5

quadratic:
x^2 + 5x + 4
x^2 - 5
4x - 2x^2

All the linear ones have no more than a first power for its variables and the quadratics have no higher than a 2 power for its variables.