The answer is d) none because substituting -1/4x + 5/3 for y in the first equation gives 3x - 3x + 5/3 = 20 so 5/3 = 20 which is not true.
Yes, the added zeros are significant. Lets say you are converting 1.23 x 10 to the power of 4. The answer would be 12,300 in which case, if you took away the zeros, the number would be 123, which is an incorrect answer.
Hope this makes sense and helps!
19 feet
convert 2 
into an improper fraction
2 = 
hence the length of the wall is 19 feet
The variables are: x, y
The constant is: 4
The coefficients are: 5, 3
The exponent is: y^2
