2x^2-7=4
subtract 4 from both sdies
2x^2-11=0
therefor
2x^2=11
divide by 2
x^2=5.5
square root both sdies
x=-2.345 or 2.345
We are going to make simultaneous equations.
x will be our $3 ice cream and y will be our $5 ice cream
Equation1 ---- x + y = 50 (the sum of all the ice creams they sell)
Equation 2 ---- 3x + 5y = 180 Sum of all the $3 and $5 ice creams is $180
Since we can't solve for both variables we will put one of the variables in terms of the other.
Take x+y=50 and subtract y from both sides. (I could have done subtracted x - it did not matter). Now we have x= ₋ y +50 (negative y +50)
Now I am going to take equation 2 and replace the x with -y +50
3 (-y +50) + 5y = 180
Now I will use the distributive law on the 3 and what's in the parentheses:
-3y + 150 + 5y = 180
Now I will combine like terms (the -3y and the 5y)
2y + 150 = 180
Now subtract 150 from both sides of the equation
2y = 30
Divide both sides by 2
and get y= 15 They sold 15 ice creams that cost $5 each
Since equation 1 is x+y=50 we can replace y with 15
x + 15 = 50 Now subtract 15 from both sides x = 35
Since x represents the $3 ice creams, they sold 35 of those.
Check:
35 X 3 = $105
15 x 5 = + <u>75
</u> $180
![(\sqrt[5]{x^{7}})^{3}=(x^{\frac{7}{5}})^{3}=x^{\frac{7\cdot3}{5}}=x^{\frac{21}{5}}](https://tex.z-dn.net/?f=%28%5Csqrt%5B5%5D%7Bx%5E%7B7%7D%7D%29%5E%7B3%7D%3D%28x%5E%7B%5Cfrac%7B7%7D%7B5%7D%7D%29%5E%7B3%7D%3Dx%5E%7B%5Cfrac%7B7%5Ccdot3%7D%7B5%7D%7D%3Dx%5E%7B%5Cfrac%7B21%7D%7B5%7D%7D)
The root is equivalent to a fractional power with that number as the denominator. Otherwise, the rules of exponents apply.
I think it would be 13 hours possibly
F(x) = 20000 (1-0.15) power x
So
f(x) = 20000 (0.85) power x
