Question

at what vale of x is the line tangent to the graph of y=x^2+3x+5 perpendicular to the line x-2y=5

Answer 1

find the derivative:
y = 2x + 3
Slope is 2
in second case slope is:
-2y = -x+5
y = 1/2 x- 5/2

Answer 2

oh wait no...

Answer 3

in second case slope is 1/2, so:
1/2 = 2x + 3

Answer 4

1 = 4x + 6
-5 = 4x
x = -5/4, check my arithmetic and answer.. but that was right lol

Answer 5

i just didnt finish it..

Answer 6

that is not a choice. the choices are -5/2, -2, -1/2, 1/2, and 5/2

Answer 7

oh sorry its not supposed to be 1/2 = 2x + 3
because we are looking for perpendicular so:
-2 = 2x + 3
-5 = 2x
x = -5/2

Answer 8

alright ty again ignore this it just helps me to type it out. find the slope of first line and plug it into the y for the second line and solve for x