Sagot :
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]
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]
[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]