Step 1a

Given points.

Explanation: Given points \$(2,3)\$ and \$(4,5)\$.

Let \$A(2,3) and B(4,5)\$.

Step 1b

Equation of a line passes through two points.

Explanation: Equation of a line passes through two points \$A(x_1,y_1) and B(x_2,y_2)\$ is \$(y - y_1) = (y_2 - y_1)/(x_2 - x_1) (x - x_1)\$.

Here \$x_1 = 2, y_1 = 3, x_2 = 4\$ and \$ y_2 = 5\$.

Step 1c

Substitute the points in the line equation formula.

Explanation:

\$(y - y_1) = (y_2 - y_1)/(x_2 - x_1) (x - x_1)\$

\$=> (y - 3) = (5 - 3)/(4 - 2) (x - 2)\$

\$=> (y - 3) = 2/2 (x - 2)\$

\$=> (y - 3) = cancel2^1/cancel2^1 (x - 2)\$

\$=> (y - 3) = 1/1 (x - 2)\$

\$=> (y - 3) = (x - 2)\$

\$=> x - y = -3 + 2\$

\$=> x - y = -1\$

\$=> x - y + 1 = 0\$.