This is the concept of simultaneous equations, the question requires us to solve the system of equations given by:
2x+4y=38
10x+3y=105
from the top equation;
2x=38-4y
dividing through by 2 we get:
x=19-2y......(*)
substituting (*) in the second equation we get:
10x+3y=105
10(19-2y)+3y=105
190-20y+3y=105
collecting like terms we get:
-20y+3y=105-190
-17y=-85
dividing both sides by -17 we get:
(-17y)/(-17)=(-85)/(-17)
y=5
thus
x=19-2y
x=19-2*5
x=19-10
x=9
thus
x=9 and y=5
Answer:

Step-by-step explanation:

I think it's B. The sum of angles in a triangle is always 180 degrees.
Answer:
W=191,000MWH S=27,000MWH
Step-by-step explanation:
OK, let's W be wind electricity generated and S, solar electricity generate.
TOTAL GENERATED: <u>218,000mwh = W + S </u>
RELATION BETWEEN W AND S: <u>W = 2,000mwh + 7S</u>
We have now two equations:
218,000 = W + S
W = 2,000 + 7S
Put th value of W into the 1st equation in order to find S:
218,000 = 2,000 + 7S + S
218,000 = 2,000 + 8S
218,000 - 2,000 = 8S
216,000 = 8S
S = 216,000/8
S = 27,000mwh
Now, we find W.
W = 2,000 + 7*27,000mwh
W = 2,000 + 189,000mwh
W = 191,000mwh