Soal No. 5 Persamaan garis #1 : 2x + y = 10 ................y = -2x + 10 gradien (m₁) = - 2 Garis berpotongan di sumbu x dan sumbu y jika y = 0, maka x₁ = 5........... (5,0) jika x = 0, maka y₁ = 10..........(0,10)
Persamaan garis #2 : x - y = 2 ................y = x - 2 gradien (m₂) = 1 Garis berpotongan di sumbu x dan sumbu y jika y = 0, maka x₂ = 2........... (2,0) jika x = 0, maka y₂ = -2. .........(0,-2)
Verified answer
Soal No 1.a + 2b = -5 ⇔ a = -2b - 5
Disubstitusikan
3a - 2b = 1
3 (-2b - 5) - 2b = 1
-6b - 15 - 2b = 1
-6b - 2b = 1 + 15
- 8b = 16
b = 16 / (- 8)
b = - 2
a = -2b - 5
a = -2(-2) - 5
a = 4 - 5
a = -1
Soal No 2.
4x - 3y = 47
3x + 2y = 34 ⇔ 2y = 34 - 3x
y = 17 - ³/₂ x
Disubstitusikan
4x - 3y = 47
4x - 3 (17 - ³/₂ x) = 47
4x - 51 + ⁹/₂ x = 47
⁸/₂ x + ⁹/₂ x = 51 + 47
¹⁷/₂ x = 98
17 x = 98 × 2
17 x = 196
x = 196 / 17
x = 11 ⁹/₁₇
y = 17 - (³/₂) (¹⁹⁶/₁₇)
y = 17 - (⁵⁸⁸/₃₄)
y = (⁵⁷⁸/₃₄) - (⁵⁸⁸/₃₄)
y = - (¹⁰/₃₄)
Soal No. 3
4m - 3n = 1 .......(× 5) 20m - 15n = 5
3m + 5n = 37 ....(× 3) 9m + 15n = 111
----------------------- (+)
29m = 116
m = 116 / 29
m = 4
4m - 3n = 1 .......(× 3) 12m - 9n = 3
3m + 5n = 37 ....(× 4) 12m + 20n = 148
--------------------------- (-)
- 29n = - 145
n = 145 / 29
n = 5
Soal No. 4
3p - 2q = 6 .......(× 3) 9p - 6q = 18
5p + 3q = 29 ....(× 2) 10p + 6q = 58
----------------------- (+)
19p = 76
p = 76 / 19
p = 4
3p - 2q = 6 .......(× 5) 15p - 10q = 30
5p + 3q = 29 ....(× 3) 15p + 9q = 87
----------------------- (-)
- 19q = - 57
q = 57 / 19
q = 3
Soal No. 5
Persamaan garis #1 :
2x + y = 10 ................y = -2x + 10
gradien (m₁) = - 2
Garis berpotongan di sumbu x dan sumbu y
jika y = 0, maka x₁ = 5........... (5,0)
jika x = 0, maka y₁ = 10..........(0,10)
Persamaan garis #2 :
x - y = 2 ................y = x - 2
gradien (m₂) = 1
Garis berpotongan di sumbu x dan sumbu y
jika y = 0, maka x₂ = 2........... (2,0)
jika x = 0, maka y₂ = -2. .........(0,-2)
Titik potong dari dua persamaan garis adalah:
-2x + 10 = x - 2
2x - 10 = -x + 2
3x = 12
x = 4
y = x - 2
y = 4 - 2
y = 2
Titik potong berada di titik (4,2)
Gambar grafik terdapat pada lampiran.