Solution:  
Using Substitution Method:
-4x+7y=-5   (Equation 1)
x-3y=-5       (Equation 2)
get the value of x from Equation 2
x=3y-5     (Equation 3)  
Put the value of x from Equation 3 in Equation 1
-4(3y-5)+7y=-5
-4(3y)+20+7y=-5
-12y+7y=-5-20
-5y=-25
Negative sign on both sides cancels each other
y=25/5
y=5
Putting value of y in equation 3
x=3(5)-5
x=15-5
x=10
Therefore,   [x,y]=[10,5]
Using Elimination Method
-4x+7y=-5   (Equation 1)
x-3y=-5       (Equation 2)
Multiply equation 2 with -4 in order to eliminate the x term
-4(x-3y)=-5*4
-4x+12y=20     (Equation 3)
Adding Equation 1 and 3
-4x+7y=-5    
-4x+12y=20    
+    -     = -   (Change Of Sign with x and y terms)
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0x-5y	= -25
-5y=-25
y=5  
Substituting y’s value is Equation 1
-4x+7(5)=-5
-4x+35=-5
-4x=-40
Cancellation of negative sign on both sides
x=40/4
x=10
[x,y]=[10,5]
 
        
             
        
        
        
Hey! 
If 112 people are getting cake and 5/8 are getting chocolate, that means the remaining will get chocolate.
8/8 - 5/8 = 3/8
3/8 are getting chocolate. You have to find 3/8 of 112.
3/8 × 112 = 336/8 = 42
42 people are getting carrot cake
:)
        
             
        
        
        
Answer:
No it is still 11 feet from the water at 2 seconds
2.1651 seconds  is when it will hit the water
Step-by-step explanation:
h(t) = -16 t^2 +75
This is the formula  for the distance
The -16t^2 is due to gravity and the 75 is the height above the bridge
We want to know the height a t =2
h(2) = -16 (2)^2 +75
h(2) =-64 +75
h(2) = 11
The rock will be 11 ft above the water
When will the rock hit the water
h = 0
0 = -16 t^2 +75
Subtract 75 from each side
-75 = -16t^2 +75-75
-75 = -16t^2 
Divide by -16
-75/-16 =  -16t^2 /-16
75/16 = t^2
Take the square root of each side.  We only take the positive square root since time must be positive
sqrt(75/16) =t
5/4 sqrt(3) = t
2.1651 seconds = t
 
        
             
        
        
        
Answer:
12
Step-by-step explanation:
Let x be the number of gallons of water in lake Mead.
Given that  there is 326099 gallons in 1 acre-foot, we calculate Mead's gallons as:

We now equate x to  ;
;

Hence, a=12