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Mathematics 16 Online
Mako178:

can someone help me with this

Mako178:

1 attachment
Diorq24:

It’s been a while since I did this negl

Mako178:

Its college precalc ive been stumped on how to do this for awhile 😭

Mako178:

the formula for exponential is \[y=ab^x\]

Mako178:

a is the initial or y intercept

Diorq24:

Yea I’m sorry man I don’t remember any of this i graduated last year

Mako178:

thanks anyways man

Mako178:

I just wanted to know how to do it Ill just get the answers then come back and learn how to do it some other time its due in 50 minutes

Mako178:

and i got like 2 questions left

Diorq24:

I can do my best

Diorq24:

I got it

Diorq24:

It’s y=25/3

Diorq24:

Wait no

Diorq24:

Y=25 (3/5)

Diorq24:

That’s your final answer

Luigi0210:

Okay this problem is messy, I can see why you'd have trouble: You'd start off by plugging a given point into the equation, so we'll use (-1, 3/5) \(\large \frac{3}{5}=ab^{-1} \) From here, solve for "a" \(\large \frac{3}{5} *b=a \) Plug "a" into the second equation, which is obtained by plugging in the second coordinate points, (2, 25/9) \(\large \frac{25}{9}=(\color{red}{\frac{3}{5}b} )b^3\) Now combine and solve for "b" \(\large \frac{25}{9}=\frac{3}{5}b^4 \) \(\large \frac{25}{9}*\frac{5}{3}=b^4 \) \(\large \frac{125}{27}=b^4\) \(\huge \sqrt[4]{\frac{125}{27} }=b\)

Luigi0210:

Now the fun part is solving for "a," which we start by plugging back in "b" into the equation: \(\huge \frac{25}{9}=a*(\sqrt[4]{\frac{125}{27}})^2 \) The exponent and 4th root can be simplified \(\huge \frac{25}{9}=a*(\sqrt{\frac{125}{27}}) \) Now just divide and you get: \(\huge \frac{ \frac{25}{9}} {( \sqrt{\frac{125}{27}}) } =a\)

Luigi0210:

Putting it together, you get this monstrosity as your answer: \(\huge y= \frac{ \frac{25}{9}} {( \sqrt{\frac{125}{27}}) } * (\sqrt[4]{\frac{125}{27}})^x\) I graphed it and the points at x=-2 and x=1 check out, but you might want to graph it too just to be sure.

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