Answer:
I will answer in a general way because the options are not given.
We know that the area of model A is smaller than the area of model B.
For model A, we have 72 shaded sections, out of 100.
Then the quotient of model A is:
72/100 = 0.72
For model B we have 10 sections, and x shaded ones.
Because model B is greater than model A, we know that:
x/10 should be larger than 72/100
then we have the inequality:
x/10 > 0.72
x > 0.72*10
x > 7.2
And we can not have more than 10 shaded sections (because there is a total of 10 sections) then:
10 ≥ x > 7.2
Then x can be any whole number in that interval.
the possible values of x are:
x = 8
x = 9
x = 10
the answer is 
subtract 6x on both sides → 
divide both sides by -2y →
The coefficient of X is -2
The difference (I'm assuming you meant difference) between 279 and 63 is
279 - 63 = 216
so divide 432 by 216
432 / 216 = 2
so the answer is 2
