(a + b) : (a - b) = 1 : 5 nilai a dan b ?

a + b = 1 ....(pers 1)
a - b = 5 ....(pers 2)

eliminasi (1) & (2)
=>dengan ditambah
a + a = 1 + 5
2a = 6
a = 3

substitusi (1)
a + b = 1
3 + b = 1
b = 1 - 3
b = (-2)