Pen=x
Pencil=y
y+0.15=x
y+x=0.69
y+y+0.15=0.69
2y=0.69-0.15
2y=0.54
y=0.54/2
y=0.27 pencils
y+0.15=x
0.27+0.15=x
0x=0.42 pen
150 pencils x0.27=40.5$
225 pens x 0.42=94.5$
Total 40.5$ + 94.50$=135 $
Supplier is right about a priče.
8x + 2y = 44
5x + 2y = 35
Since 2y is already common, there is no need for multiplication. Just reverse the signs on the equation.
Like this;
8x + 2y = 44
-5x - 2y = -35
All the additions become subtractions and vice versa.
-2y and +2y get cancelled.
Leaving;
8x = 44
-5x = -35
Now, subtract again.
8x - 5x = 3x
44 - 35 = 9
So;
3x = 9
x = 9 / 3
x = 3
We found 'x' and now we have to find 'y'.
Just substitute.
[8 x 3] + 2y = 44
24 + 2y = 44
2y = 44 - 24
2y = 20
y = 20 / 2
y = 10
Now, we re-check;
[8 x 3] + [2 x 10] = 44
24 + 20 = 44
Explaining the error for #9b is simply doing the whole sum.
Hope this helped! :) I tried my best to explain.
Step-by-step explanation:
is similar to 
so we can write the ratio
Solving for x, we get
The answer is A) √3
cot(-5π/6)=1/tan(-5π/6)
=1/tan(-(5π/6)
Use the property: tan(-x)=-tan(x)
=1/tan(5π/6)
-(1/tan(5π/6))
tan(5π/6)=-√3/3
-(1/-√3/3)
-(1/-√3/3)
=√3
