bantuan kakak sangat dibutuhkan sekali

a.
F = m*a
(mQ)g - (mP)g = (mQ + mP)a
70 - 30 = (7 + 3)a
40 = 10a
a = 4

b.
T1 = T2
WQ-T2 = m*a
70 - T2 = 7(4)
70 - T2 = 28
T2 = 42