1. Which of the following represents a function?
x -2 -1 0 -1 -2
y 2 3 4 5 6

x 1 1 0 2 2
y 1 2 3 4 5

x 1 2 3 4 5
y 2 2 3 3 4

x 1 1 1 1 1
y 2 3 4 5 6

2. What is the domain of the function: {(2, 1); (4, 2); (6, 3); (8, 4)}?
{1, 2, 3, 4}
{1, 2, 3, 4, 6, 8}
{2, 4, 6, 8}
{6, 8}

3. What is the range of the function: {(2, 1); (4, 2); (6, 3); (8, 4)}?
{1, 2, 3, 4}
{1, 2, 3, 4, 6, 8}
{2, 4, 6, 8}
{6, 8}

4. Suppose p varies directly with d, and p = 7 when d = 3. What is the value of d when p = 28?
4/3
12
16
140/3

5. Given the function T(z) = 7 − z, find T(−4).
−11
11
−3
3
6. What is the equation of the graph?

f(x) = − |x| + 2
f(x) = − |x| − 2
f(x) = − |x + 2|
f(x) = − |x − 2|
7. The number of calories burned, C, varies directly with the time spent exercising, t. When Dennis walks for 4 hours, he burns 800 calories. Which of the following equations shows this direct linear variation?
C = t
C = 800t
C = 4t
C = 200t

1 Which of the following represents a function x 2 1 0 1 2 y 2 3 4 5 6 x 1 1 0 2 2 y 1 2 3 4 5 x 1 2 3 4 5 y 2 2 3 3 4 x 1 1 1 1 1 y 2 3 4 5 6 2 What is the dom class=


Answer :

1. 3rd one, because for each x there's only one y.

2. The domain are x's, so it's {2, 4, 6, 8}

3.
The range are y's, so it's {1, 2, 3, 4}

4.
[tex]p=kd\\ 7=3k\\ k=\dfrac{7}{3}\\ p=\dfrac{7}{3}d\\ d=\dfrac{3}{7}p\\ d=\dfrac{3}{7}\cdot28=12[/tex]

5.
[tex]T(-4)=7-(-4)=7+4=11[/tex]

6. [tex]f(x) = - |x| + 2[/tex]

7.
[tex]C=kt\\ 800=4k\\ k=200\\ C=200t[/tex]


[tex]1.\\\#1\ not\ because\ for\ x=-2\to y=2\ and\ y=6\\\#2\ not\ because\ for\ x=1\to y=1\ and\ y=2\\\#3\ \boxed{IT'S\ OK}\leftarrow answer\\\#4\ not\ because\ for\ x=1\to y=2\ and\ y=3\ and...[/tex]

[tex]2.\ (x;\ y)\to x\in D-domain\\\\therefore:\\\\\{(2;1);\ (4;2);\ (6;\ 3);\ (8;\ 4)\}\\\\\boxed{The\ domain\ D=\{2;\ 4;\ 6;\ 8\}}[/tex]

[tex]3.\ (x;\ y)\to y\in Range\\\\\{(2;\ 1);\ (4;\ 2);\ (6;\ 3);\ (8;\ 4)\}\\\\\boxed{the\ range:\{1;\ 2;\ 3;\ 4\}}[/tex]

[tex]4.\\\frac{p}{d}=constans\\\\\frac{28}{d}=\frac{7}{3}\ \ \ \ |cross\ multiply\\\\7\cdot d=3\cdot28\ \ \ \ |divide\ both\ sides\ by\ 7\\\\d=\frac{84}{7}\\\\\boxed{d=12}[/tex]

[tex]5.\ T(z)=7-z\\\\T(-4)\to z=-4\\\\put\ the\ value\ of\ z\ to\ (7-z):\\\\T(-4)=7-(-4)=7+4=\boxed{11}[/tex]

[tex]6.\\y=|x|\to\ the\ axis\ of\ symmetry\ is\ OY\ (S_{OY})\\\\y=-|x|\to\ the\ axis\ of\ symmetry\ is\ OX\ (S_{OX})\\\\so....\ the\ y-intercept\ is\ (0;\ 2),\ therefore\ answer\ is\ \boxed{f(x)=-|x|+2}[/tex]

[tex]7.\\\begin{array}{ccc}C&-&t\\800&-&4\end{array}\ \ \ \ |cross\ multiply\\\\4C=800t\ \ \ \ \ |divide\ both\ sides\ by\ 4\\\\\boxed{C=200t}[/tex]