Question

find solutions of the follopwing sets of simultaneous equations by the substitution method 3a+7b+33,a+3b+33.

Answer 1

3a+7b+33=0........1
a+3b+33=0...........2
multiply eqn 1 by 1 and eqn 2 by 3
3a+7b+33=0
3a+9b+99=0
- -
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-2b-66=0
-2b=66
b=-66/2
b=-33
put the value of y in eqn 1
3a+7b+33=0
3a+7*-33+33=0
3a-231+33=0
3a-198=0
3a=198
a=198/3
a=66
(a=66 and b=-33)

Answer 2

3a+7b=33
3a=33-7b
a=33-7b/3