4. Straight Line
A linear function graphs as a line, and is written in the form f(x)=mx+b, with m being the slope and b being the y-intercept. A quadratic function can graph as any of the conic sections, including a parabola, hyperbola, ellipse, or circle. A quadratic function is a function in which the highest variables power is exactly 2. The most commonly known quadratic function is a parabola, which has an increasing slope in one direction of the x-axis and a decreasing slope in the other. It is a curve that looks similar to a u, and it is written in the form f(x)=ax²+bx+c; c is the y-intercept, and the sign of a determines whether the curve opens up or down. An exponential function is often of the form f(x)=a^(bx)+c, and c can be any polynomial or constant. The function approaches a limit as x approaches infinity in one direction, and approaches infinity in the other direction, determined by the size of a and the sign of b. A straight line refers to a function of the form f(x)=c, c being a constant value.