jika (a, b, c) adalah solusi sistem persamaan linear y+z=10 3z-4y=0 dan x+2z=18 maka nilai a+b+c

jawab

y + z = 10......||kali 3
-4y + 3z = 0...||kali 1

3y + 3z = 30
-4y + 3z = 0......|(-)
7y = 30
y = 30/7

y + z= 10
z = 10 - y
z = 10 - 30/7
z = 40/7

x + 2z = 18
x = 18 - 2z
x = 18 - 2(40/7)
x = 18 - 80/7
x = 46/7

x= a 
y = b
z = c

a + b + c = x + y + z = 46/7 +30/7 +40/7 = 116/7
a + b + c = 16 ⁴/₇