Mintol bisa kamu kerjakan semua itu mintol

1) 3x = 11 + 2y
3x - 2y = 11
2x + y = 5 |×2
maka
3x - 2y = 11
4x + 2y = 10
-----------------(+)
7x = 21
x = 3
• 3x - 2y = 11 |×2
2x + y = 5 |×3
maka
6x - 4y = 22
6x + 3y = 15
------------------(-)
- 7y = 7
y = - 1
hp = { 3,-1 }

2) 2x + y = 3
y = - 2x + 3
subtitusi ke :
x - 3y = 5
x - 3(-2x + 3) = 5
x + 6x - 9 = 5
7x = 5 + 9
7x = 14
x = 2
subtitusi ke :
y = - 2x + 3
y = - 2(2) + 3
y = - 4 + 3
y = - 1
hp = { 2 , - 1 }

4) misal
buku = x
pensil = y
10x + 2y = 16.200 |×2
5x + 4y = 9.900
maka
20x + 4y = 32.400
5x + 4y = 9.900
---------------------------(-)
15x = 22.500
x = 1.500
subtitusi ke :
5x + 4y = 9.900
5(1.500) + 4y = 9.900
7.500 + 4y = 9.900
4y = 9.900 - 7.500
4y = 2.400
y = 600
nilai 3x + 5y
= 3(1.500) + 5(600)
= 4.500 + 3.000
= 7.500
jadi harga 3 buku & 5 pensil = 7.500

5) misal
p = x + 5
l = x
K = 2 × ( p + l )
58 = 2 × ( x + 5 + x )
58 ÷ 2 = 2x + 5
29 = 2x + 5
29 - 5 = 2x
24 = 2x
x = 12
maka
p = x + 5 = 12 + 5 = 17 cm
l = x = 12 cm
L = p × l
= 17 × 12
= 204 cm²