subtitusikan p.s : nomor 2 pke pemisalan

1. 2x + y = 7 | x-3
5 x - 3y = 1 | x1

-6x + -3y = -21
5x -3y = 1
___________ —
11x=22
x=2

sub. ke pers 1
2x + y= 7
2(2)+y =7
y=7-4
y=3

hp(2,3)

2. misal 1/x =a dan 1/y=b
a + 2b = 1 | x5
3a + 10b = 4 |x1

5a + 10b = 5
3a + 10b = 4
_____________ —
2a= 1
a=½
1/x = ½
x=2

subs a ke pers 1
a + 2b = 1
(½) + 2b = 1
2b = 1 - ½
b= ½ per 2
b=1/4
1/y = 1/4
y=4

hp (2,4)

3. ½x + ⅓y = -1 | x2
⅓x - ¼y = 5 | x3

x + ⅔y = -2
x - ¾y = 15
____________—
17/12 y =17
y=12

sub y ke pers 1
½x + ⅓y = -1
½x + ⅓(12) = -1
½x + 4 = -1
x= -5 per ½
x = -10/2
x=-5

hp (-5,12)

4.6x + 2y = 11 | x1
3x - 4y = 8 | x2

6x + 2y = 11
6x - 8y = 16
_____________—
10y=-5
y=-½

sub y ke pers 1
6x + 2y = 11
6x + 2(-½)=11
6x - 1 = 11
6x = 12
x = 2

hp (2, -½)