Friday

August 29, 2014

August 29, 2014

Posted by **Bailey** on Tuesday, June 16, 2009 at 10:08pm.

This is what i did:

x(2-x)+15<0

2x - x^2 + 15 < 0

-x^2 + 2x + 15 < 0

(x+3)(-x+15) < 0

-3<x<5

but when i check by subbing the number, say, 4 into x, the answer is always greater than zero. And the correct answer should be x<3 or x>5, which also seems wrong, because when i sub a number, say 2, into the inequality, the answer is still greater than 0.

what is wrong??? I've checked the things i did so many times and i don't see anything wrong????

- weird maths sum!! -
**bobpursley**, Tuesday, June 16, 2009 at 10:30pmLook at this:

(x+3)<0

x<-3

Not greater than.

-x+5<0

x>5

so x<-3 and x>5

**Related Questions**

maths inequalities... - Find the range of values of k for which the expression x...

Pure Mathematics - 1. Given that the straight line y=c-3x does not intersect the...

maths - find the range of values for k for which the circle x^2+y^2=25 and the ...

maths-urgently - let y = 3x+ 10 - x^2, where x and y are positive whole no. find...

Maths (Simultaneous equations) - You know f(x)= ax˛ + bx + c. Well when you get ...

weird maths question? - This is the question, but i get the wrong answer. In a ...

Maths - For this question, use the copy of the Random Number table provided at ...

maths - the sum of 3rd and 5th terms of an a.p is 38 and sum of 7th and 10th ...

Alegbra - I've learned that the difference between domain and range is........

maths - The sum of a number and four times its reciprocal is 5.Find possible ...