Reduce to l form $ax ^ 2 + bx + c$ in the first member, $0$ in the 2nd member, then use the discussion of the sign of$T = ax^2+ bx+c$ $\Delta = b^2 - 4ac$ ------------------------------- Si $\Delta\lt 0$: $T$ a le sign of $a$ ------------------------------- Si $\Delta = 0$: $T$ has the sign of $a$, if $x$ is not equal to the root $x_0$ $T = 0$, if $x$ is equal to the root $x_0$ ------------------------------- If $\Delta \gt 0$: $T = 0$, if $x$ is equal to the roots $x_1$ or $x_2$ $T$ has the sign of $a$, if $x$ is outside the roots $x_1$ and $x_2$ $T$ has the sign of $-a$, if $x$ is between the roots $x_1$ and $x_2$ ------------------------------- -------------------------------

Got it !

## Solve:

 $-x^2 \lt x - 12$ $x^2 \lt 8 - 7x$ $x^2 + 31x \gt -150$ $x^2 -3x \geq -2$ $x^2 + 31x \gt -150$ $5 - 4x \gt x^2$ $4x(x+3) \geq -9$ $5 - 4x \gt x^2$