Question

Write an equation of a line that goes through the point (-9, 3), and is perpendicular to the line 3x + y = 5

Answer 1

To find the slope of the line, first find the slope of 3x + y = 5, and then its opposite reciprocal.

3x + y = 5
y = -3x + 5
the slope of 3x + y = 5 is -3.

the slope is -3, so the opposite reciprocal slope is 1/3.

the equation of any line is y = ax + b
to find this line, y = 3, x = -9, and the slope is 1/3.

3 = -9a + b
3 = -9 (1/3) + b
3 = -3 +b
b = 6

substitute a and b into the equation
y = ax + b
y = 1/3x + 6

the equation of the line is y = 1/3x + 6.