Subtract : 3a ( a + b + c ) - 2b (a - b + c ) from 4c ( -a + b + c)
Please explain the various steps.
solve it this way
3a(a+b+c) -2b(a-b+c) = 3a2 + 3ab +3ac -2ab + 2b2 -2bc
=3a2 +ab + 3ac + 2b2 -2bc ....... (1)
Now evaluate the following
4c(-a+ b+c) = -4ac + 4bc +4c2 ....... (2)
Now subtract (1) from (2)
(-4ac + 4bc + 4c2) -(3a2 +ab + 3ac + 2b2 -2bc) = - 4ac +4bc+4c2 -3a2 -ab -3ac -2b2 +2bc
=(-4ac -3ac) + (4bc +2bc) +4c2 -3a2 -ab -2b2
(-4ac + 4bc + 4c2) -(3a2 +ab + 3ac + 2b2 -2bc) = -7ac + 6bc +4c2-3a2-ab-2b2
which is the answer.