enter image description here Function is $f(x)= ax^425x^3+2x^2+25x+b $ it passes through (7,E) E= 1296 and there is a zero of 1
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3Please do not use pictures for critical portions of your post. Pictures may not be legible, cannot be searched and are not viewable to some, such as those who use screen readers. – Brian Mar 22 '19 at 14:32

Welcome to stackexchange. When you [edit] the question to ask it directly rather than with a hard to read image, be sure to tell us what you tried and where you are stuck. Please use mathjax: https://math.meta.stackexchange.com/questions/5020/mathjaxbasictutorialandquickreference – Ethan Bolker Mar 22 '19 at 14:35

@EnriqueRodriguez Please add the function and your work into your question. If you show your effort appropriately, it is more likely that somebody will also put his/her effort into providing you some help. – Ertxiem  reinstate Monica Mar 22 '19 at 14:42

@Ertxiem is this better? – Enrique Rodriguez Mar 22 '19 at 15:22

@Brian i added the function is this better? – Enrique Rodriguez Mar 22 '19 at 15:23
1 Answers
You can find $a$ and $b$ as a system of equations:
We know that for $x=7$, $f(x)=1296$, this will be one equation on $a$ and $b$.
And for $x=1$, $f(x) = 0$, this will give another equation on $a$ and $b$.
Can you write down the equations and solve the system or do you need more help?
Edit: The equations will be: $$\begin{cases} a \times 7^4  25 \times 7^3 + 2 \times 7^2+25 \times 7 + b = 1296 \\ a \times (1)^4  25 \times (1)^3 + 2 \times (1)^2+25 \times (1) + b = 0 \end{cases}$$
Edit 2: If you subtract the first equation from the second you get an equation without $b$: $$a \times (7^4(1)^4)  25 \times (7^3(1)^3) + 2 \times (7^2(1)^2) + 25 \times (7(1)) = 1296 \ .$$ I was a bit lazy and I did not compute the powers of $7$. :)
With this last equation, you'll be able to compute the value of $a$. To obtain the value of $b$ you can use one of the other equations (I suggest using the one with the smaller numbers).
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still a little confused first time doing this! how do i get the a and b out of this 2 equations? cause a and b are still both in there? i can slove when its one variable but not 2. – Enrique Rodriguez Mar 22 '19 at 16:01

@EnriqueRodriguez: I added another step in the solution. I believe that you can now compute the final result on your own. – Ertxiem  reinstate Monica Mar 22 '19 at 19:30