Question
A and B are constants such that the graphs of the lines 3x - 4y = 7 and 8x + Ay = B are perpendicular and intersect at (5,2). What is A+B?
Answers
Anonymous
4 y = 3 x - 7 ----> y = (3/4) x - 7/4
slope = (3/4)
so the slope of the second one = (-4/3)
A y = - 8 x + B
y = -8/A x + B/A
so
(-4/3) = -8/A
looks like A = 6
goes through (5,2)
2 = (-4/3)(5) + B/6
12 = -40 + B
B = 52
6+52 = 58
slope = (3/4)
so the slope of the second one = (-4/3)
A y = - 8 x + B
y = -8/A x + B/A
so
(-4/3) = -8/A
looks like A = 6
goes through (5,2)
2 = (-4/3)(5) + B/6
12 = -40 + B
B = 52
6+52 = 58
Isreal
Thank you! You helped me 100%.
Anonymous
You are welcome.