Answer:
[tex]\textsf{a)} \quad y=1.8(3.2)^x[/tex]
[tex]\textsf{b)} \quad y=5(7)^x[/tex]
Step-by-step explanation:
[tex]\boxed{\begin{minipage}{9 cm}\underline{General form of an Exponential Function}\\\\$y=ab^x$\\\\where:\\\phantom{ww}$\bullet$ $a$ is the initial value ($y$-intercept). \\ \phantom{ww}$\bullet$ $b$ is the base (growth/decay factor) in decimal form.\\\end{minipage}}[/tex]
Part (a)
Given ordered pairs:
- (0, 1.8)
- (1, 5.76)
- (2, 18.432)
The y-intercept is the y-value when x = 0.
Therefore, as the y-intercept is 1.8, a = 1.8.
[tex]\implies y=1.8b^x[/tex]
Substitute point (1, 5.76) into the equation and solve for b:
[tex]\begin{aligned} y&=1.8b^x\\\implies 5.76&=1.8 \cdot b^1\\5.76&=1.8b\\b&=\dfrac{5.76}{1.8}\\b&=3.2\end{aligned}[/tex]
Therefore, the exponential equation is:
[tex]\boxed{y=1.8(3.2)^x}[/tex]
To complete the given table, simply substitute the values of x into the found equation:
[tex]\begin{array}{c|l}x&\phantom{189}y\\\cline{1-2} \vphantom{\dfrac12}}0&\phantom{18}1.8\\\vphantom{\dfrac12}}1&\phantom{18}5.76\\\vphantom{\dfrac12}}2&\phantom{1}18.432\\\vphantom{\dfrac12}}3&\phantom{1}58.9824\\\vphantom{\dfrac12}}4&188.74368\end{array}[/tex]
Part (b)
Given ordered pairs:
The y-intercept is the y-value when x = 0.
Therefore, as the y-intercept is 5, a = 5.
[tex]\implies y=5b^x[/tex]
Substitute point (2, 245) into the equation and solve for b:
[tex]\begin{aligned} y&=5b^x\\\implies 245&=5 \cdot b^2\\49&=b^2\\b&=\sqrt{49}\\b&=7\end{aligned}[/tex]
Therefore, the exponential equation is:
[tex]\boxed{y=5(7)^x}[/tex]
To complete the given table, simply substitute the values of x into the found equation:
[tex]\begin{array}{c|l}x&\phantom{11}y\\\cline{1-2} \vphantom{\dfrac12}}0&\phantom{1111}5\\\vphantom{\dfrac12}}1&\phantom{111}35\\\vphantom{\dfrac12}}2&\phantom{11}245\\\vphantom{\dfrac12}}3&\phantom{1}1715\\\vphantom{\dfrac12}}4&12005\end{array}[/tex]
