Problema Solution

Find equations (in slope-intercept form) for the line;

a. parallel to the line 24x − 3y = 7 and passing through (−1, 4).

b. perpendicular to the line y = −(4/5)X-7 passing through (1, 6).

Answer provided by our tutors

A "slope-intercept" form of a line is:


y = mx + b


where "m" is the slope and "b" gives the y-intercept.


a.parallel to the line 24x − 3y = 7 and passing through (−1, 4)


since the slopes of parallel lines are equal we will write 24x − 3y = 7 in slope intercept form


24x − 3y = 7


3y = 24x - 7 divide both sides by 3


y = 8x - 7


thus m = 8


now the only thing left to find is b


y = 8x + b goes trough (−1, 4) that is


4 = 8(-1) + b


b = 12


finally we have the slope-intercept equation of the wanted line:


y = 8x + 12


b.perpendicular to the line y = −(4/5)x − 7 and passing through (1, 6)


for perpendicular line the perpendicular slopes are negative reciprocals of each other


the slope of the line y = −(4/5)x − 7 is -4/5


negative reciprocal fo -4/5 is -(-4/5)^(-1) = 5/4 thus m = 5/4


now the only thing left to find is b


y = (5/4)x + b goes trough (1, 6) that is


6 = (5/4)*1 + b


b = 6 - 5/4


b = 19/4


finally we have the slope-intercept equation of the wanted line:


y = (5/4)x + 19/4