An airplane has a mass of 1.9e6 kg and the air flow past the
lowersurface of the wings at 90 m/s. if the wings have surfacearea
of 1.6e3 m^3, how fast must the air over the upper surface ofthe
wing if the plane is to stay in the air. consider onlythe bernoulli
effect.

Explanation:

The Bernoulli equation is:

(1)

Now let's apply the equation (1), for our case:

(2)

here we assume that h is the same in both cases so it canceled out.

Solving the equation for v₁ we have:

(3)

Now, we know that pressure P=F/A (force over area)

(4)

Combining (3) and (4), we can find v1.

I hope it helps you!  

a and b sometimes have a positive value