use distributive property
0.5 x -10 = -5
0.5 x k = 0.5k
0.5(-10 + k) = 0.5k -5
Answer:
son's present age = 30
father's present age=60
Step-by-step explanation:
his son's present age = x years
his father's present age = 2x years
before 20 years his son's age=(x-20) years
before 20 years father's age=(2x-20) years4(x-20)=(2x-20)
4x-80=2x-20
4x-2x=80-20
2x=60
x=30
