Solve the poynomial inequality. Write the answer in interval notation. Could you show your work since I don't get these. Thanks
(T-7)(T+1) is less than 0.
x^3 + 36 is greater than to 4x^2 + 9x
Solve the poynomial inequality. Write the answer in interval notation. Could you show your work since I don't get these. Thanks
(T-7)(T+1) is less than 0.
x^3 + 36 is greater than to 4x^2 + 9x
Hello,
A product is negative if the two factors are of different sign.
-> T-7>0 and T+1<0
Or T-7<0 and T+1>0
For this one,x^3 + 36 is greater than to 4x^2 + 9x
x^3+36>4x^2+9x
<=> (x^3-9x)+(36-4x^2)>0
<=> x(x²-9)+4(9-x²)>0
<=> (x²-9)(x-4)>0
A product is positive if its factors are of the same sign.
-> x²-9>0 and x-4>0
Or x²-9<0 and x-4<0
Ouuuh, I missed a mistake :
Do you know why, in my first post, I only said that there were two solutions ?Divide by x.
x + 2 less than -1
Because you don't know if x is positive or negative.
If it's positive, it keeps the sign of the inequality.
If it's negative, < will become >.
An example :
6>4
If you divide both sides by -2, is it -3>-2 or -3<-2 ?
Be careful about this