kerjakan soal berikut dengan cara subtitusi 1. x = 2y + 7 x+ 3y - 1 =0

x- 2y= 7
x +3y= 1
kayak gini ngga?

x = 2y + 7...............(#1)
x + 3y - 1 = 0 ⇒ x + 3y = 1...........(#2)

Substitusi (#1) ke (#2)

x + 3y = 1
(2y + 7) + 3y = 1
5y = 1 - 7
5y = 6
y = ⁶/₅
y = 1 ¹/₅

x + 3y = 1
x + 3(⁶/₅) = 1
x + ¹⁸/₅ = 1
x = ⁵/₅ - ¹⁸/₅
x = - ¹³/₅
x = - 2 ³/₅

Pembuktian :
x + 3y = 1
(-¹³/₅) + 3(⁶/₅) = 1
¹⁸/₅ - ¹³/₅ = 1
⁵/₅ = 1
1 = 1..........Terbukti