SOLUTION: How do I factor completely 3x^2-x-10

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Question 629253: How do I factor completely 3x^2-x-10
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+3x%5E2+-+x+-+10+
You can use the quadratic formula.
When the equation has the form:
+ax%5E2+%2B+b%2Ax+%2B+c+, the roots are:
+x+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+
+a+=+3+
+b+=+-1+
+c+=+-10+
+x+=+%28-%28-1%29+%2B-+sqrt%28+%28-1%29%5E2+-+4%2A3%2A%28-10%29+%29%29+%2F+%282%2A3%29+
+x+=+%28+1+%2B-+sqrt%28+1+%2B+120+%29%29+%2F+6+
+x+=+%28+1+%2B-+sqrt%28+121+%29%29+%2F+6+
+x+=+%28+1+%2B+11+%29+%2F+6+
(1) +x+=+2+
and, using the negative square root,
+x+=+%28+1+-+11+%29+%2F+6+
+x+=+-10%2F6+
(2) +x+=+-5%2F3+
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From (1) and (2), I get:
(1) +x+-+2+=+0+
+x+%2B+5%2F3+=+0+
multiply both sides by +3+
(2) +3x+%2B+5+=+0+
and
+%28+x+-+2+%29%2A%28+3x+%2B+5+%29+=+3x%5E2+-+x+-+10+
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check:
+3x%5E2+-x+-+10+=+3x%5E2+-+x+-+10+
OK