SOLUTION: I am stuck and do not know how to solve this problem. log(4x) – log(12 + √x) = 2

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: I am stuck and do not know how to solve this problem. log(4x) – log(12 + √x) = 2      Log On


   



Question 938956: I am stuck and do not know how to solve this problem.
log(4x) – log(12 + √x) = 2

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Convert +2+ to a log
+2+=+log%28100%29+
+log%284x%29+-+log%28%28+12%2B+sqrt%28x%29%29%29+=+log%28100%29+
+log%28%28+4x+%2F+%28+12+%2B+sqrt%28x%29+%29%29%29+=+log%28100%29+
+4x+%2F+%28+12+%2B+sqrt%28x%29+%29+=+100+
+4x+=+100%2A%28+12+%2B+sqrt%28x%29%29+
+4x+=+1200+%2B+100%2Asqrt%28x%29+
+x+=+300+%2B+25%2Asqrt%28x%29+
+25%2Asqrt%28x%29+=+x+-+300+
square both sides
+625x+=+x%5E2+-+600x+%2B+90000+
+x%5E2+-+1225x+%2B+90000+=+0+
-----------------------------
Use the quadratic formula to solve
+x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+1+
+b+=+-1225+
+c+=+90000+
You can finish