SOLUTION: Twice the square of a certain number added to 3times the number makes 90.find the number

Algebra ->  Test -> SOLUTION: Twice the square of a certain number added to 3times the number makes 90.find the number      Log On


   

Question 519719: Twice the square of a certain number added to 3times the number makes 90.find the number
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
x = a certain number
.
2x^2 +3x = 90
.
2x^2 +3x -90 = 0
.
factor
.
(2x +15)(x -6) = 0
.
x = -15/2 or 6
.
+graph%28500%2C500%2C-10%2C10%2C-100%2C100%2C2%2Ax%5E2%2B3%2Ax-90%29+