Find the equation of a line perpendicular to the line 4y = 7x + 3 which passes through (-3, 1)
A
7y + 4x + 5 = 0
B
7y - 4x - 5 = 0
C
3y - 5x + 2 = 0
D
3y + 5x - 2 = 0
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
Equation: 4y = 7x + 3
\(\implies y = \frac{7}{4} x + \frac{3}{4}\)
Slope = coefficient of x = \(\frac{7}{4}\)
Slope of perpendicular line = \(\frac{-1}{\frac{7}{4}}\)
= \(\frac{-4}{7}\)
The perpendicular line passes (-3, 1)
\(\therefore\) Using the equation of line \(y = mx + b\)
m = slope and b = intercept.
\(y = \frac{-4}{7} x + b\)
To find the intercept, substitute y = 1 and x = -3 in the equation.
\(1 = \frac{-4}{7} (-3) + b\)
\(1 = \frac{12}{7} + b\)
\(b = \frac{-5}{7}\)
\(\therefore y = \frac{-4}{7} x - \frac{5}{7}\)
\(7y + 4x + 5 = 0\)
Source: Myschool Past Questions Archive (Record #55436)