5 x 6 + 7? Is that what the answer is, I didn't get the question towards the end. :)
The red pencil is 6 and the blue one is 3 so blue +blue(3+3)=6
Your answer would be x = 3.0645
CHECK
log (3.0645 + 1) ?=? -(3.0645)2 + 10
log 4.0645 ?=? -9.3912 + 10
0.609 ?=? 0.609
Hope this helps!
So in short your answer is x = 3.0645