SOLUTION: Find two possitive numbers whose product equals 357, and whose difference is 4. (use systems of equations to solve)?

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Question 447523: Find two possitive numbers whose product equals 357, and whose difference is 4. (use systems of equations to solve)?
Found 2 solutions by jorel1380, josmiceli:
Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
xy=357
x-y=4
----------
x-4=y
x(x-4)=357
x2-4x-357=0
(x-21)(x+17)=0
x=21 or -17
Throwing out the negative answer, we get x=21, y=17..

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+m%2An+=+357+
+m+-+n+=+4+
+n+=+m+-+4+
By substitution:
+m%2A%28m+-+4%29+=+357+
+m%5E2+-+4m+-+357+=+0+
Use the quadratic formula
m+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+1+
+b+=+-4+
+c+=+-357+
m+=+%284+%2B-+sqrt%28+%28-4%29%5E2+-+4%2A%281%29%2A%28-357%29+%29%29%2F%282%2A1%29+
m+=+%284+%2B-+sqrt%28+16+%2B+1428+%29%29%2F+2+
m+=+%284+%2B-+sqrt%28+1444+%29%29%2F2+
+m+=+%284+%2B+38%29%2F2+
+m+=+42%2F2+
+m+=+21+
+n+=+m+-+4+
+n+=+21+-+4+
+n+=+17+
The numbers are 17 and 21