Question 82 (v)
Subtract
2ab + 5bc - 7ac from 5ab - 2bc - 2ac + 10abc
We have, 2ab + 5bc - 7ac and 5ab - 2bc - 2ac + 10abc
The required difference is given by (5ab - 2bc - 2ac + 10abc) - (2ab + 5bc - 7ac)
= 5ab - 2bc - 2ac + 10abc - 2ab - 5bc + 7ac
= (5ab - 2ab) + (-2bc - 5bc) + (-2ac + 7ac) + 10abc
[grouping like terms]
= 3ab - 7bc + 5ac + 10abc