Answer:
Step-by-step explanation:
A) When the first equation is multiplied by 5 and the second equation by –6 ,
the equations become,
35x + 60y=54
-30x - 60y=60
Hence we can eliminate y by adding the equation.
B) When the first equation is multiplied by -5 and the second equation by 6 ,
the equations become,
-35x - 60y=54
30x + 60y=60
Hence we can eliminate y by adding the equation.
C) When the first equation is multiplied by -5 and the second equation by 7,
the equations become,
-35x - 60y=54
35x - 70y=60
Hence we can eliminate x by adding the equation.
D) When the first equation is multiplied by 5 and the second equation by -7,
the equations become,
35x + 60y=54
-35x - 70y=60
Hence we can eliminate x by adding the equation.
E) When the first equation is multiplied by -5 and the second equation by 10,
the equations become,
-35x - 60y=54
50x - 100y=60
Hence we can not eliminate x by adding the equation.
Answer:
x = 16
Step-by-step explanation:
(x+2) + (7x+2) + (3x) = 180
<em>Add like terms</em>
7x + x + 3x = 11x
2 + 2 = 4
11x + 4 = 180
<em>Subtract 4</em>
11x + 4 = 180
11x = 176
<em>Divide by 11</em>
11x = 176
x = 16
The coefficient is the number 6/7.
Number 1. <span>So the duck's OWN speed (if flying without any wind) with the wind behind him is:
Where x/10 is the wind speed
The duck's OWN speed (if flying without any wind) with the wind against him is:
Where x/10 is the wind speed Remember
So we have two equations that must equal each other since they both represent the duck's speed.
We need to rearrange to find x
Add x/10 to both sides and subtract (1600/10 from both sides gives:
so x must be 400/10 which 40 metres per minute.
Number 2. </span>let s=salmon and c=current <span>
upstream __ s-c=100m/20 min __ s-c=5m/min
downstream __ s+c=100m/8min __ s+c=12.5m/min
adding the two equations __ s-c+(s+c)=5+12.5 __ 2s=17.5 __ s=8.75m/min
substituting __ 8.75+c=12.5 __ c=3.75m/min</span>
