First we need to determine what the 6 angles must add to. Turns out we use this formula
S = 180(n-2)
where S is the sum of the angles (result of adding them all up) and n is the number of sides. In this case, n = 6. So let's plug that in to get
S = 180(n-2)
S = 180(6-2)
S = 180(4)
S = 720
The six angles, whatever they are individually, add to 720 degrees. The six angles are y, y, 2y-20, 2y-20, 2y-20, 2y-20, <span>
They add up and must be equal to 720, so let's set up the equation to get...
(y)+(y)+(</span>2y-20)+(2y-20)+(2y-20)+(<span>2y-20) = 720
Let's solve for y
</span>y+y+2y-20+2y-20+2y-20+2y-20 = 720
10y-80 = 720
10y-80+80 = 720+80
<span>10y = 800
</span>
10y/10 = 800/10
y = 80
Now that we know the value of y, we can figure out the six angles
angle1 = y = 80 degrees
<span>angle2 = y = 80 degrees
</span><span>angle3 = 2y-20 = 2*80-20 = 140 degrees
</span>angle4 = 2y-20 = 2*80-20 =<span> 140 degrees
</span><span>angle5 = 2y-20 = 2*80-20 = 140 degrees
</span>angle6 = 2y-20 = 2*80-20 =<span> 140 degrees
</span>
and that's all there is to it
1. since the equations equal each other
2x+19=x+7
-x -x
x+19=7
-19 -19
x= -12
sub into y= x+7
y= -12+7
y= -5
2. x+2y=-7
<span>x+y+23=0
i don't know what the second equation is equal to, i'll assume 0
2y=x-7
y=1/2x-7/2
sub this into x+y+23=0
x+1/2x-7/2+23=0
3/2x+39/2=0
-39/2 -39/2
3/2x= -39/2
x=-39/2 / 3/2
x= -13
sub into y=1/2x-7/2
y=1/2(-13)-7/2
y= -10
3. </span>x+5y=2
<span>x=-4y+5
</span>sub x=-4y+5 into x+5y=2
-4y+5+5y=2
y+5=2
-5 -5
y= -3
sub y =-3 into x =-4y+5
x=-4(-3)+5
x= 17
4. 3x+y=9
<span>y=-5x+9
</span>sub -5x+9 into 3x+y=9
3x+(-5x+9)=9
3x-5x+9=9
-2x+9=9
-9 -9
-2x=0
x=0
sub into y=-5x+9
y=-5(0)+9
y=9
Answer: 4
Step-by-step explanation: b=c2﹣a2=52﹣32=4
