SOLUTION: The square of a negative number is fifty-four more than three times the negative number. Find the number.

Algebra ->  Square-cubic-other-roots -> SOLUTION: The square of a negative number is fifty-four more than three times the negative number. Find the number.      Log On


   

Question 1124445: The square of a negative number is fifty-four more than three times the negative number. Find the number.
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

if a negative number is -x
and if the square of a negative number is 54 more than three times the negative number, we have
%28-x%29%5E2=3%2A%28-x%29%2B54...since %28-x%29%5E2=%28-x%29%28-x%29=x%5E2,we have
x%5E2=-3x%2B54
x%5E2%2B3x-54=0...actor
x%5E2%2B9x-6x-54=0
%28x%5E2%2B9x%29-%286x%2B54%29=0
x%28x%2B9%29-6%28x%2B9%29=0
%28x+-+6%29+%28x+%2B+9%29+=+0
solutions:
if %28x+-+6%29++=+0->x=6-> since we are looking for negative number, disregard this solution
i +%28x+%2B+9%29+=+0->highlight%28x=-9%29-> your number