SOLUTION: Please help 1.What is the value of k so that the equation 2x2 + 4x - 17 = kx has roots numerically equal but opposite in sign? 2.A rocket is shot vertically into the air. I

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Please help 1.What is the value of k so that the equation 2x2 + 4x - 17 = kx has roots numerically equal but opposite in sign? 2.A rocket is shot vertically into the air. I      Log On


   

Question 998318: Please help
1.What is the value of k so that the equation 2x2 + 4x - 17 = kx has roots numerically equal but opposite in sign?
2.A rocket is shot vertically into the air. Its height at any time t, in seconds, can be determined by the equation s = -16t2 + 184t. When will the it reach its maximum height of 529 ft?
Please help
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Equal but opposite in sign.
f%28x%29=%28x-a%29%28x%2Ba%29=x%5E2-ax%2Bax-a%5E2=x%5E2-a%5E2
So there can be no x term.
2x%5E2%2B4x-17=4x
2x%5E2-17=0
2x%5E2=17
x%5E2=17%2F2
x=0+%2B-+sqrt%2817%2F2%29
.
.
.
s=-16t%5E2%2B184t=529
-16t%5E2%2B184t=529
Complete the square,
-16%28t%5E2-%2823%2F2%29t%29=529
-16%28t%5E2-%2823%2F2%29t%2B%2823%2F4%29%5E2%29=529-16%2823%2F4%29%5E2
-16%28t-23%2F4%29%5E2=529-529
-16%28t-23%2F4%29%5E2=0
t-23%2F4=0
t=23%2F4