diketahui SPLDV 2×+y=1 ×-3y=-10 memiliki penyelesaian x=a dan y=b nilai 3a+4b adlah

semoga membantu ya ...????

2x + y = 1 /×1. 2x + y = 1
x - 3y = -10 /×2. 2x - 6y = -20
––––––––– –
7y = 21, y= 21/7 = 3

2x + y = 1
2x + 3 = 1
2x=1-3
x = -2/2 = -1

x = a= -1
Y = b= 3

3a + 4b = -3 + 12
= 9