We can use the points given to solve for the slope.
Slope formula: y2-y1/x2-x1
7-3/4-1
4/3
Find the y-intercept.
y = mx + b
3 = 4/3(1) + b
3 = 4/3 + b
5/3 = b
The slope of a perpendicular line is the opposite and reciprocal.
4/3 -> -3/4
Write the new equation.
y = -3/4x + 5/3
Best of Luck!