Question

Consider two points $P_1(2,7)$ and $P_2(6,15)$. Write the equation and draw a straight line through these points.

Answer 1

Step 1. Obtain the gradient or slope, which is $m$.
Step 2. $c$ can be found by using the $(x,y)$ values at any given point.

Step. Gradient =$\frac{y_2-y_1}{x_2-x_1}=\frac{15-7}{6-2}=\frac{Height}{Distance}=\frac{8}{4}=2$

So, $y=2x+c$

Step2. To find c put $x=2$,$y=7$ or $x=6$,$y=15$ in Eq.(i)

$7=2\times 2+c\Rightarrow c=3$

So,m=2,c=3.

Hence, the equation becomes $y=2x+3$