Given the inequality: x(6x−5)>0 To solve this inequality, we must first solve the corresponding equation: x(6x−5)=0 Solve: Expand the expression in the equation x(6x−5)=0 We get the quadratic equation 6x2−5x=0 This equation is of the form
a*x^2 + b*x + c = 0
A quadratic equation can be solved using the discriminant. The roots of the quadratic equation: x1=2aD−b x2=2a−D−b where D = b^2 - 4*a*c - it is the discriminant. Because a=6 b=−5 c=0 , then
D = b^2 - 4 * a * c =
(-5)^2 - 4 * (6) * (0) = 25
Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or x1=65 x2=0 x1=65 x2=0 x1=65 x2=0 This roots x2=0 x1=65 is the points with change the sign of the inequality expression. First define with the sign to the leftmost point: x0<x2 For example, let's take the point x0=x2−101 = −101 = −101 substitute to the expression x(6x−5)>0 10(−1)(−5+10(−1)6)>0
14
-- > 0
25
one of the solutions of our inequality is: x<0
_____ _____
\ /
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x2 x1
Other solutions will get with the changeover to the next point etc. The answer: x<0 x>65