SOLUTION: 3a - 2b =21 a + 3b = -4 what is the value of each variable (a and b)?

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Question 126002: 3a - 2b =21
a + 3b = -4
what is the value of each variable (a and b)?
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

3a+-+2b+=21..............(1)
a+%2B+3b+=+-4..............(2)
take (2) and solve for a
a+%2B+3b+=+-4..............(2)
a+=+-3b+-4..........(I)..........substitute in (1)
3%28-3b+-4%29+-+2b+=21
-9b+-12+-+2b+=21
-11b+=21%2B12
-11b+=+33
b+=+33%2F-11
highlight%28b+=+-3%29

a+=+-3b+-4..........(I)
a+=+-3%28-3%29+-4
a+=+9+-4
highlight%28a+=+5%29...............

check:
3%2A5+-+2%28-3%29+=21..............(1)
15+%2B+6+=21
21+=21