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Graphical method is irrelevant in this problem.
It is intended to be solved by the pure Algebra method.
Your starting system of equations is
4x^2 - y^2 = 15 (1)
2x - y = 5 (2)
Decompose first equation as the difference of squares
(2x-y)*(2x+y) = 15 (3)
In this equation, replace (2x-y) by 5, based on equation (2)
5*(2x+y) = 15
which gives
2x + y = 15/5 = 3.
So, now you have two linear equations instead of (1) and (2)
2x + y = 3 (4)
2x - y = 5 (5)
To solve, add the equations. You will get
4x = 3 + 5 = 8, hence x = 8/4 = 2.
Then from equation (3)
y = 3 - 2x = 3 - 2*2 = -1.
ANSWER. x = 2; y = -1.
Solved.
