A pentagon has 5 sides. A hexagon has 6 sides. If the pentagon has 5 sides that each measure 6 inches, then the perimeter would be 30 inches. If the hexagon has 6 sides that measure 5 inches each, then the perimeter is also 30. The shapes have the same perimeter.
Since 2x appears on the left side of both equations, that term can be eliminated by subtraction, which is what the first choice suggests.
The result will be ...
3y = 7 -4y +5 . . . . . . . . . second equation subtracted from the first
7y = 12 . . . . . . add 4y
y = 12/7 . . . . . . divide by 7
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However, the fact that 2x is by itself on the left side of the second equation suggest that <em>substitution</em> may also be a good option. Perhaps an equally good first step is to use the expression in the second equation to substitute for 2x in the first:
(4y -5) +3y = 7
Either way, the resulting equation is 2-step.
7y = 12 . . . add 5
y = 12/7 . . . divide by 7
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The other suggested "first steps" do nothing useful.