Let's plug in (18,10) into each answer choice until we find the one that has it as a solution.
A) 2x - y = 26
2(18) - 10 = 26
36 - 10 = 26
26 = 26
Your answer is A.
I'll just do the rest to show that you the they are incorrect.
B) x + y = 18
18 + 10 = 18
28 ≠ 18
C) 2x - 2y = 36
2(18) - 2(10) = 36
36 - 20 = 36
16 ≠ 36
D) x - y = -28
18 - 10 = -28
8 ≠ -28
Your answer is A) 2x - y = 26.
To change a percent to a fraction, you remove the percent sign and put the given number over 100. For example, if you are given 78%, it would be 78/100 or 39/50
As x = 5 & z=12,
<span>2/3 = y /(xz) = y/(5*12) </span>
<span>= y/60 </span>
<span>so y / 60 = 2/3 </span>
<span>y = (2*60)/3 </span>
<span>= 40</span>