It is good equation. Look, that:
81 = 3 x 3 x 3 x 3 = 3^4.
So you have to solve:
3^x = 3^4 
exponents have to be the same, so
x=4
That's mean that A(4) = 81
        
                    
             
        
        
        
y = ( x + 9 )^2 - 2
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Answer: 
Option C: 6x-5y=15
Explanation:
y = -5/6x +8
8 is the <u>y-intercept</u>
-5/6x is the <u>slope</u>
when a slope is in <u>fraction form</u> the numerator is the y direction over the denominator how much the line changes in the x direction
::: (\_(\ Hope
*: (=' :') this
•.. (,('')('') helped :)
 
        
             
        
        
        
Answer:
y =  60
Step-by-step explanation:
From the  information we get:
x  quantity of 4 dollars  coffee used in the mix
y  quantity of 7 dollars  coffee used in the mix
For the quantity of coffee to be sold a 7 $/pound  ( 90 pounds)
Then  6*90  =  540  $
Therefore
x  +  y  =  90     and
4*x  +  7*y  =  540
A two equations system we solve for x and y
y =  90  -  x
4*x  +  7* ( 90  -  x ) = 540
4*x  +  630 - 7*x  =  540
- 3*x  =  - 90
x = 30 pounds   and
y  =  90  -  30
y  =  60
We should use  60 pounds of the seven $ coffee