So first you have to do 18 multiply by 2/9. This gets you 4, next you multiply by 1/2. This gets you 2.
ANSWER: She will have 2 stamps left.
Question (1):The general formula of the quadratic equation is:
ax² + bx + c = 0
The given equation is:
5x² + 9x = 4
Rearrange the given equation to look the standard one:
5x² + 9x - 4 = 0
Now, compare the coefficients in the given equation with the standard one, you will find that:
a = 5, b = 9 and c = -4
Question (2):The given expression is:
-5 + 2x²<span> = -6x
</span>Rearrange this expression to be in standard form:
2x² + 6x - 5 = 0
This means that:
a = 2
b = 6
c = -5
The roots of the equation can be found using the formula in the attached image.
Substituting in this formula with the given a, b and c, we would find that the correct choice is third one (I have attached the correct choice)
Question (3):Quadratic formula (the one used in the previous question, also shown in attached images) is the best method to get the solution of any quadratic equation. This is because, putting the equation in standard form, we can simply get the values of a, b and c, substitute in the formula and get the precise solutions of the equation.
Hope this helps :)
![\bf \textit{using the 2nd fundamental theorem of calculus}\\\\ \cfrac{dy}{dx}\displaystyle \left[ \int\limits_{0}^{x}\ cos^{-1}(t)dt \right]\implies cos^{-1}(x) \\\\\\ f'(0.3)\iff cos^{-1}(0.3)\approx 1.26610367277949911126](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Busing%20the%202nd%20fundamental%20theorem%20of%20calculus%7D%5C%5C%5C%5C%0A%5Ccfrac%7Bdy%7D%7Bdx%7D%5Cdisplaystyle%20%5Cleft%5B%20%5Cint%5Climits_%7B0%7D%5E%7Bx%7D%5C%20cos%5E%7B-1%7D%28t%29dt%20%5Cright%5D%5Cimplies%20cos%5E%7B-1%7D%28x%29%0A%5C%5C%5C%5C%5C%5C%0Af%27%280.3%29%5Ciff%20cos%5E%7B-1%7D%280.3%29%5Capprox%201.26610367277949911126)
now.. 0.3 is just a value...we'e assuming Radians for the inverse cosine, so, if you check, make sure your calculator is in Radian mode
3 is the answer to your question
By 16+ do you mean positive 16 because if you do then it is less than 19+