Two perpendicular lines form an angle of 90o at the intersection point. That is, they make 90o at the intersection point. To know that a line is perpendicular to another line, check its gradients or slopes.

The focus of our previous tutorial was about the equation of a parabola. A parabola that has its vertex at the origin is of the form: $$y^{2}=4 p x$$ From this general equation, we can readily determine if the parabola opens upwards, downwards, left, or right.

We are already aware of the solution of a system of two linear equations. To find a solution to a system of linear equations, we apply the Gaussian elimination, algebraic substitution, or graphical method. We covered that in our previous tutorial.

Rates of doing work differ from person to person. Even if they are machines, their rate of doing work is slightly different even if they look very identical. Think of taps filling a tank. We can’t assume that both can take the same time filling the tank. That is because we don’t know about the water pressure from the source.

Any object that moves covers a distance over time. Using these two parameters, we can calculate the speed. Speed is simply the rate of displacement. There is a formula that connects these three entities. If you encounter any distance, speed, time graph, then remember that the formula is the only way to finding the solution.