Could someone please help me understand what I am doing wrong? I have watched videos on Khan Academy and somehow I'm still getting these answers wrong. You also have to use significant figure rules on these equations.

It is often necessary to do calculations using scientific notati following calculations. 1.00 x 10-8 + 7.92 x 104 x = 8.92x10^-4 2.86x10^-3 8.78 x 10-4 + 2.69 x 105 4.01 x 104 7.00 x 10-6 8.84x10^-2 (1.00 x 10-6) (7.92 x 104 ) An error has been detected in your answer. Check for typos, miscalculations etc. before submitting your