Chapter 10

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=x^{2}-6 x+8 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=-x^{2}+8 x-16 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=-x^{2}+2 x-7 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=2 x^{2}-4 x+1 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=3 x^{2}-6 x-1 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=2 x^{2}-4 x+2 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=-x^{2}-4 x+2 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=x^{2}+6 x+8 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=-16 x^{2}+24 x-9 $$

In the following exercises, graph by using intercepts, the vertex, and the axis of symmetry. $$ y=3 x^{2}+18 x+20 $$

In the following exercises, find the maximum or minimum value. $$ y=2 x^{2}+x-1 $$

In the following exercises, find the maximum or minimum value. $$ y=-4 x^{2}+12 x-5 $$

In the following exercises, find the maximum or minimum value. $$ y=x^{2}-6 x+15 $$

In the following exercises, find the maximum or minimum value. $$ y=-x^{2}+4 x-5 $$

In the following exercises, find the maximum or minimum value. $$ y=-9 x^{2}+16 $$

In the following exercises, find the maximum or minimum value. $$ y=4 x^{2}-49 $$

In the following exercises, solve. Round answers to the nearest tenth. An arrow is shot vertically upward from a platform 45 feet high at a rate of \(168 \mathrm{ft} / \mathrm{sec}\). Use the \(\quad\) quadratic \(\quad\) equation \(h=-16 t^{2}+168 t+45\) to find how long it will take the arrow to reach its maximum height, and then find the maximum height.

In the following exercises, solve. Round answers to the nearest tenth. A stone is thrown vertically upward from a platform that is 20 feet high at a rate of \(160 \mathrm{ft} / \mathrm{sec}\). Use the quadratic equation \(h=-16 t^{2}+160 t+20\) to find how long it will take the stone to reach its maximum height, and then find the maximum height.

In the following exercises, solve. Round answers to the nearest tenth. A computer store owner estimates that by charging \(x\) dollars each for a certain computer, he can sell \(40-x\) computers each week. The quadratic \(\quad\) equation \(R=-x^{2}+40 x\) is used to find the revenue, \(R,\) received when the selling price of a computer is \(x\). Find the selling price that will give him the maximum revenue, and then find the amount of the maximum revenue.

In the following exercises, solve. Round answers to the nearest tenth. A retailer who sells backpacks estimates that, by selling them for \(x\) dollars each, he will be able to sell \(100-x\) backpacks a month. The \(\quad\) quadratic \(\quad\) equation \(R=-x^{2}+100 x\) is used to find the \(R\) received when the selling price of a backpack is \(x\). Find the selling price that will give him the maximum revenue, and then find the amount of the maximum revenue.

In the following exercises, solve. Round answers to the nearest tenth. A rancher is going to fence three sides of a corral next to a river. He needs to maximize the corral area using 240 feet of fencing. The quadratic equation \(A=x(240-2 x)\) gives the area of the corral, \(A\), for the length, \(x,\) of the corral along the river. Find the length of the corral along the river that will give the maximum area, and then find the maximum area of the corral.

In the following exercises, solve. Round answers to the nearest tenth. A veterinarian is enclosing a rectangular outdoor running area against his building for the dogs he cares for. He needs to maximize the area using 100 feet of fencing. The quadratic equation \(A=x(100-2 x)\) gives the area, \(A\), of the dog run for the length, \(x,\) of the building that will border the dog run. Find the length of the building that should border the dog run to give the maximum area, and then find the maximum area of the dog run.