Jawab:
[20.] y = 3x-11 (A.) ✔️
[21.] Luas = 234 m² (A.)✔️
[22.] (4.) 16, 30, 34 (D.) ✔️
[23.] Jarak = 25 km (B.) ✔️

Penjelasan dengan
langkah-langkah:
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[20.] Diketahui
(3, -2)    x₁ = 3   y₁ = -2
(4, 1)      x₂ = 4   y₂ = 1
Cari persamaan garis!
y-y₁ = [(y₂-y₁)/(x₂-x₁)] (x-x₁)
y-(-2) = [(1-(-2))/(4-3)] (x-3)
y+2 = [(1+2)/(4-3)] (x-3)
y+2 = [3/1] (x-3)
y+2 = 3(x-3)
y+2 = 3x-9
y = 3x-9-2
y = 3x-11 (A.) ✔️
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[21.] Persegi panjang
Panjang lebih 5 m dr Lebar
P = 5 + L
Keliling adalah 62 m
2(P+L) = 62
maka
2(5+L+L) = 62
2(5+2L) = 62
10+4L = 62
4L = 62-10
4L = 52
L = 52/4
-->  L = 13 m
Cari panjang (P)
P = 5 + L = 5 + 13
-->  P = 18 m
Luas = P × L
Luas = 18×13 m²
Luas = 234 m² (A.)✔️
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[22.] Tripel Pythagoras
hasil kiri = hasil kanan
a(1.) 7, 24, 26
7² + 24² = 26²
49 + 576 = 676
625 ≠ 676 tidak sama ❌
↓
b(2.) 12, 15, 20
12² + 15² = 20²
144 + 225 = 400
369 ≠ 400 tidak sama ❌
↓
c(3.) 10, 24, 25
10² + 24² = 25²
100 + 576 = 625
676 ≠ 625 tidak sama ❌
↓
Kesimpulan
Yang merupakan tripel
harusnya {10, 24, 26}
dan {7, 24, 25}
↓
d (4.) 16, 30, 34
16² + 30² = 34²
256 + 900 = 1.156
1.156 = 1.156 BENAR! ✔️
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[23.] Diketahui:
Barat = 75 km
Selatan = 20 km
Timur = 60 km
Dicari jarak terdekat (jarak)
Jarak² =
(Barat-Timur)²+Selatan²
maka
Jarak² = (75-60)²+20²
Jarak² = 15²+20²
Jarak² = 225+400
Jarak² = 625

Jarak = 25 km (B.) ✔️
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<(7o7)>