Question 480424
x^2+y=21..........1
-4x-y=0...........2

From (1) y=21-x^2

substitute y in (2)

-4x-(21-x^2)=0

-4x-21+x^2=0

x^2-4x-21=0

x^2-7x+3x-21=0

x(x-7)+3(x-7)=0
(x-7)(x+3)=0
x=7 OR -3

when x = 7 y = -28  (7,-28)
when x= -3 y= 12    (-3,12)

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