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Can anyone please explain how to solve the following inequality?
x(3x + 2) > (x + 2)^2
3 Answers
- 1 decade agoFavorite Answer
Distribute the x on the left and square the right side. So then it would be
3x^2 + 2x > x^2 + 4x + 4
subtract x^2 and 2x from both sides
2x^2 > 2x + 4
factor a 2 from 2x + 4
2x^2 > 2(x + 2)
divide by 2 on both sides
x^2 > x + 2
subtract an x and a 2
x^2 - x - 2 > 0
factor
(x-2)(x+1)>0
x>2 or x>-1
so I guess you could write it as -1<x>2
hope I helped!!
- 1 decade ago
it is easy.
to prove the inequality, simplify both these.
x(3x + 2) > (x + 2)^2
3x^2+2x > x^2 + 4 +4x
2x^2 - 2x > 4
2x(x-1)>4
let x = 2
both are equal.
x = 3
equation satisfies inequality.
hence for every value of x above 2 , inequality occurs
- M3Lv 71 decade ago
solve it as a quadratic first
and then test the 3 parts that the answers can give
by first testing the middle part.
if it doen't fit the bill, the other 2 will
the quadratic will yield the solution (-1,2)
<------ | ------------- | -------->
. . . .-1 . . . . . . . 2
the middle part on testing doesn't fit, so
ans: x < -1 or x > 2
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