SOLUTION: Find values for m and b in the following system so that the solution to the system is (–4, 5). mx + 5y = 21 and –4x – 4y = b

Algebra ->  Equations -> SOLUTION: Find values for m and b in the following system so that the solution to the system is (–4, 5). mx + 5y = 21 and –4x – 4y = b      Log On


   

Question 682249: Find values for m and b in the following system so that the solution to the system is (–4, 5). mx + 5y = 21 and –4x – 4y = b
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
(x,+y)= (-4,+5)
mx+%2B+5y+=+21.......eq. 1 and
-4x-4y=b....eq. 2
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mx+%2B+5y+=+21.......eq. 1..plug in x=-4 and +y=5
m%2A%28-4%29+%2B+5%2A5+=+21.......solve for m
-4m+%2B25+=+21
-21+%2B25+=4m
4=4m
highlight%28m=1%29

-4x-4y=b.....plug in x=-4 and +y=5
-4%28-4%29-4%2A5=b......solve for b
16-20=b
highlight%28-4=b%29