Answer: option d.
Step-by-step explanation:
If <em>y </em>varies directly as <em>x</em> and <em>z</em>, the form of the equation is:
![y=kxz](https://tex.z-dn.net/?f=y%3Dkxz)
Where<em> k</em> is the constant of variation.
If y=4 when x=6 and z=1 then substitute these values into the expression and solve for <em>k:</em>
![4=k(6)(1)\\4=6k\\k=\frac{4}{6}\\\\k=\frac{2}{3}](https://tex.z-dn.net/?f=4%3Dk%286%29%281%29%5C%5C4%3D6k%5C%5Ck%3D%5Cfrac%7B4%7D%7B6%7D%5C%5C%5C%5Ck%3D%5Cfrac%7B2%7D%7B3%7D)
<em> </em>Substitute the value of <em>k</em> into the expression. Then, the equation is:
![y=\frac{2}{3}xz](https://tex.z-dn.net/?f=y%3D%5Cfrac%7B2%7D%7B3%7Dxz)
To find the value of <em>y </em>when x=7 and z=4, you must substute these values into the equation. Therefore you obtain:
![y=k=\frac{2}{3}(7)(4)](https://tex.z-dn.net/?f=y%3Dk%3D%5Cfrac%7B2%7D%7B3%7D%287%29%284%29)
![y(7,4)=\frac{56}{3}](https://tex.z-dn.net/?f=y%287%2C4%29%3D%5Cfrac%7B56%7D%7B3%7D)
<em> </em>
I think it is 64 cause i multiplied
<span>14% per year
</span>14% /12 = 1.2% is <span> the monthly growth rate</span>
Next time, please share the answer choices.
Starting from scratch, it's possible to find the roots:
<span>4x^2=x^3+2x should be rearranged in descending order by powers of x:
x^3 - 4x^2 + 2x = 0. Factoring out x: </span>x(x^2 - 4x + 2) = 0
Clearly, one root is 0. We must now find the roots of (x^2 - 4x + 2):
Here we could learn a lot by graphing. The graph of y = x^2 - 4x + 2 never touches the x-axis, which tells us that (x^2 - 4x + 2) = 0 has no real roots other than x=0. You could also apply the quadratic formula here; if you do, you'll find that the discriminant is negative, meaning that you have two complex, unequal roots.
(3 * 10,000) + ( 9* 1,000) + ( 5* 1)