Jawaban:

Metode subtitusi

2. a. x = 4

3x + 2y = 10

3(4) + 2y =10

2y = 10 - 12

2y = -2

y = -1

hp ( 4, -1)

b. 8p + 5q =6

5p - q = 12

- q = -5p + 12

q = 5p - 12

8p + 5q = 6

8p + 5(5p - 12) = 6

8p + 25p - 60 = 6

33p = 6 + 60

p = 66/33

p = 2

q = 5p - 12

q = 5(2) -12

q = -2

p,q =( 2, -2)

c. y = 3x

y = 3 × -3/2 = -9/2 = -4,5

x - 3y = 12

x - 3(3x) = 12

x -9x = 12

-8x = 12

× = - 12/8

x = - 3/2

x= -3/2 dan y = -4,5

d. x+4y = 6

x = -4y + 6

x = -4(4)+6

x = -16+6

x = -10

3x + 6y =-6

3( -4y + 6) + 6y = -6

-12y + 18 + 6y = -6

-6y = -6 - 18

y = - 24/-6

y = 4

jadi x = -10 dan y = 4