Answer:
x=10
y=25
Step-by-step explanation:
3x-10+5x+30+6x+20=180
14x+40=180
14x=180-40
14x=140
x=10
9x-10=4y-20
9(10)-10=4y-20
90-10=4y-20
80=4y-20
80+20=4y
100=4y
25=y
Let the Length of River D be : P
Given : River C is 100 Miles Longer than River D
⇒ Length of River C = P + 100
Given : The Sum of Both Rivers is 5570 Miles
⇒ P + (P + 100) = 5570
⇒ 2P + 100 = 5570
⇒ 2P = 5570 - 100
⇒ 2P = 5470
⇒ P = 2735
⇒ Length of River D is : 2735 Miles
⇒ Length of River C is : (P + 100) = (2735 + 100) = 2835 Miles
The given expression is

Let's replace x = 7 and y = -2.

<h2>Therefore, the value of the expression is 20.</h2>
for the value of x is to factor the quadratic, set each factor equal to zero, and then solve each factor.
Answer:
83.4
Step-by-step explanation:
Area of a Regular Polygon: L (of side) times apothem (height) x 1/2
L : 13.9
Looking at the triangle we can assume the height would be 12 since its logical that 3 of the 4 lines can fit in the middle of the triangle.
H: 12
13.9 x 12 = 166.8
166.8/2 = 83.4