tolong kerjakan nomor 1,2,3,4,dan5 pakai cara.. besok dikumpul..

Semoga bermanfaat ya

1). Misal,
harga 1 pasang sepatu = x
harga 1 buah tas = y

3x + 5y = 290.000 |×2| 6x + 10y = 580.000
4x + 2y = 200.000 |×5| 20x + 10y = 1.000.000

Eliminasi
6x + 10y = 580.000
20x + 10y = 1.000.000
__________________-
-14x = -420.000
x = -420.000/-14
x = 30.000

Substitusi
3x + 5y = 290.000
3(30.000) + 5y = 290.000
90.000 + 5y = 290.000
5y = 290.000 - 90.000
5y = 200.000
y = 200.000/5
y = 40.000

Harga 2 pasang tas dan 2 pasang sepatu
= 2x + 2y
= 2(30.000) + 2(40.000)
= 60.000 + 80.000
= 140.000

2).
x² - 3x - 28 = 0
(x + 4)(x - 7) = 0
x + 4 = 0/ x - 7 = 0
x = -4/x = 7
3).
Keliling kebun = π × d
Keliling kebun = 22/7 × 42
Keliling kebun = 132 m

Jarak antarpohon = 4 m
Banyak pohon akasia yang ditanam
= Keliling kebun/jarak antar pohon
= 132/4
= 33 pohon
4).
Keliling kubus = 4 × s
60 = 4 × s
s = 60/4
s = 15 cm

Luas permukaan kubus = 6 × s²
= 6 × 15²
= 6 × 225
= 1.350 cm²

Volume = s × s × s
= 15 × 15 × 15
= 3.375 cm³

5).
Luas permukaan balok tanpa tutup
= pl + 2pt + 2lt
= (12 × 9) + 2(12 × 2) + 2(9 × 2)
= 108 + 2(24) + 2(18)
= 108 + 48 + 36
= 192 m²