The valued of \( 25 x^{2}+16 y^{2}+40 x y \) at \( x=1 \) and \( y=-1 \) is \( \begin{array}{ll}\text { (a) } 1 & \text { (b) } 2 \\ \text { (c) } 81 & \text { (d) }-49\end{array} \)

USING EQUATIONS to solve WORD PROBLEMS Directions: Set up and solve an equation for 12. Find three consecutive even integers such that of the smallest integer and twice the median integer is 20 more than the largest integer.

a) \( f(x)=|x+4|+2 \) b) \( f(x)=- \) c) \( f(x)=3 x^{2}-x-2 \)

9. An ice manufacturing machine requires 10 minutes to warm up before the production of ice begins. The weight, in tonnes, of ice produced varies directly as the number of hours of production. Given that 20 tonnes of ice are produced when the machine is run for half an hour, find the weight of ice manufactured when the machine is run for \( 1 \frac{3}{4} \) hours.

There are 56 sheep in a paddock. Each sheep is either white or black. There are 6 times as many white sheep as there are black sheep. How many black sheep are in the paddock?

1: \( 6 x+6 z=6 \)