SOLUTION: HELP...i got 2 different answers from two tutors...solve this quadratic inequality. 25x^+16<40x...My answer was x<4/5 one tutor agreed and one said there was no solution as

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Question 5912: HELP...i got 2 different answers from two tutors...solve this quadratic inequality.
25x^+16<40x...My answer was x<4/5
one tutor agreed and one said there was no solution as you can not take the sqrt of zero...anybody out there that can knows for sure??
Thanks Caroline
Answer by Abbey(339) About Me  (Show Source):
You can put this solution on YOUR website!
I answered you incorrectly. I read this as 25x%5E2%2B16=40x rather than 25x%5E2%2B16%3C40x
To solve this problem:
25x^2+16<40x
set this as an equal sign:
25x^2+16=40x
subtract 40x from both sides:
25x^2-40x+16=0
(5x-4)(5x-4)=0
x=4/5 You have two choices: your solution set can be from negative infinity to 4/5 or from 4/5 to infinity:
Test using the numbers 3/5 (if the solution set is less than 4/5 then this number will be included) Make a second test with the number 1 (if the solution set is from 4/5 to infinity, then the number 1 will be included in the set):
If we put 1 back into the equation:
25(1)^2+16<40(1)
25(1)+16<40
41<40 THIS IS NOT A TRUE STATEMENT, SO THE SOLUTION SET IS NOT GREATER THAN 4/5.
25(3/5)^2+16<40(3/5)
25(9/25)+16<24
9+16<24
25<24. This is not a true statement so the solution set cannot be less than 4/5 either
so there is not a solution to this problem.