Question

If a-8,b-(-2) and c-3,Find the value:
12 bc-5 ac by 2a b c-4bc

Answer 1

Answer:

Step-by-step explanation:

The quickest way is to add the given equations together :

Given. #1. a+b=8,

Given. #2. b+c=10

Given. #3. c+a=12

>> (a+b) + (b +c) +(c +a) = (8 + 10 + 12)

>> (2a + 2b + 2c) = 30

Answer. (a + b + c) = 15.

The answer may be checked using elimination.

#1. a+b=8,

#2. b+c=10

#3. c+a=12

From. #2. - #1. >> #4. c - a = 2.

From. #4 + #3. >> #5. 2c = 14 >> c = 7.

From. #5. put c = 7 into #2 >> b = 10 - 7 = 3

Hence : a = 5; b = 3; c = 7.

Answer : ( a + b + c ) = 15

Agreed and checked.