X-2y=-5……(1)X²+y²=25…….(2)

Dik:
x – 2y = -5, maka x = -5 + 2y   (1)
x^2 + y^2 = 25 (2)

jawab:
substitusikan x = -5 +2y ke x^2 + y^2 = 25

(2y – 5)^2 + y^2 = 25
4y^2 - 20y + 25 +y^2 =25 (jadikan salah satu ruasnya 0)
5y^2 -20y + 25 – 25 = 0
5y^2 – 20y = 0
5y (y – 4) = 0

didapat y = 4, sub ke x = -5 + 2y
x = -5 + 2.4
x = -5 +8
x = 3

X – 2y = -5
X = 2y – 5
X^2 + Y^2 = 25
(2y – 5)^2 + Y^2 = 25
4y^2 – 20y + 25 + y^2 = 25
5y^2 – 20y = 0
5y(y-4) = 0
5y = 0 => y = 0, atau
Y-4 = 0 => y = 4
Y=0, maka X – 2y = -5
X – 0 = -5
X = -5
Atau
Y=4
X = 2y-5 = 2(4)-5 = 8-5 = 3
Hp= (-5,0) & (3,4)