we can solve this equation by substitution method so

we put y=3x from equation 2 in equation 1

we get

2x-3(3x)=-7

2x-9x=-7

-7x=-7

divide both side by -7 we get

x=1

Now put x=1 in equation 2 , we get

y=3(1)

y=3

so the solution set of these equation is

S.S= {1,3}

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