415 + 815 + 1315 = 2545
815 + 34 = 849
It is not possible to "solve" b+815 because it is an expression - not an equation or inequality.
9:30.
When tan A = 815, sin A = 0.9999992 and cos A = 0.0012270 so that sin A + cos A*cos A*(1-cos A) = 1.00000075, approx.
6 + 3 + 21 + 63 + 21 = 114
21
815 in Roman numerals is DCCCXV.
21+21+19+19=80
21+21+17=59
(21-21)+(21-21)+21 = 0+0+21 = 21
815 = 815.0