Respuesta :

x + 3x + 7y = 41
2(3x + 7y) = 66

Simplified:
4x + 7y = 41
3x + 7y = 33  (I just divided the 2nd equation by 2)

Subtract the 2nd from the 1st
x = 8
That was easy!

Now plug in 8 in for x
3(8) + 7y = 33
24 + 7y = 33
7y = 9
y = 9/7
a)
x+3x+7y = 41
4x + 7y = 41

2(3x+7y) = 66
6x+14y = 66

answer
4x + 7y = 41
6x+14y = 66
b)
solve
4x + 7y = 41
6x+14y = 66
divide 2nd equation by 2
3x + 7y = 33

now you have
4x + 7y = 41
3x + 7y = 33
------------------subtract
x = 8

4x + 7y = 41
4(8)+ 7y = 41
32 + 7y = 41
7y = 41 - 32
7y = 9
y = 9/7

3x = 3(8) = 24 
7y=7(9/7) = 9

answer 
Length =9
width = 24