We can solve this problem by using PEMDAS
PEMDAS stands for
Parenthesis
Exponents
Multiply
Add
Subtract
So start with (P+3) () is a parenthesis
As the general formular for a straight line is
![y = mx + c](https://tex.z-dn.net/?f=y%20%3D%20mx%20%2B%20c)
m represents the gradient
c represents the point at which the line crosses the y axis.
Therefore you simply plug the numbers into the equation.
![y = 3x + 7](https://tex.z-dn.net/?f=y%20%3D%203x%20%2B%207)
You can work out whether 2 lines are perpendicular by multiplying their gradients. The product of the gradient of perpendicular lines will always be -1.
If lines are perpendicular, M1× M2 = − 1
So you can rearrange the equation to get M2=-1/M1.
As they perpendicular they have to intercept at the same point on the Y axis therefore you get the equation