Substitution

If $x=-2$ and $y=6$, evaluate: $5x-6y$

If $x=3$ and $y=-3$, evaluate: $-2x+3y$

If $x=-2$ and $y=-2$, evaluate: $5x+8y$

If $x=-1$, evaluate: $4x^{2}-5x-6$

If $x=20$, evaluate: $\sqrt{5x}$

If $x=-5$, evaluate: $-2x^{2}-9x-2$

If $x=2$, evaluate: $8x-11$

If $x=5$ and $y=5$, evaluate: (3x − 3) / (3y − 19)

If $x=5$ and $y=3$, evaluate: $-6x+7y$

If $x=4$ and $y=-2$, evaluate: $4x-2y$

If $x=-2$, evaluate: $-6x^{2}-3x-3$

If $x=2$, evaluate: $2x^{2}-4x-3$