SOLUTION: Is 5 the solution of 10x - x^2 = 3x - 10. In my answer, I said 'no'. I got -10 = 5. I also got the answer 40 = 5.

Algebra ->  Equations -> SOLUTION: Is 5 the solution of 10x - x^2 = 3x - 10. In my answer, I said 'no'. I got -10 = 5. I also got the answer 40 = 5.       Log On


   



Question 12265: Is 5 the solution of 10x - x^2 = 3x - 10. In my answer, I said 'no'. I got -10 = 5. I also got the answer 40 = 5.
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
how can you get an answer like 40=5 and see that as a reasonable answer? "40 equals 5"...40 does not equal 5, it equals 40. 40 equalling 5 is nonsense as is -10=5.

Solution:
10x+-+x%5E2+=+3x+-+10
10x+=+x%5E2+%2B+3x+-+10
0+=+x%5E2+%2B+3x+-10x+-+10
or
x%5E2+%2B+3x+-10x+-+10+=+0
x%5E2+-+7x+-+10+=+0

you have a quadratic. You need to learn how to solve quadratics: it is a large part of maths courses.

trying to factorise this...you cannot. So you need the quadratic formula. Are you sure the question is correct? not +10 perhaps?

jon.