Answer :

AL2006

-- You know that the area of every rectangle is (its length) times (its width).

-- Area of the screen you have now = (10.8cm) x (6.1cm) = 65.88 cm²

-- Area of the screen on the new phone = (12.4cm) x (6.9cm) = 85.56 cm²

Say !  Are you supposed to write an equation to find the difference ?
OK.
                     Difference = (L₂W₂) - (L₁W₁)

L₂ and W₂ are the length and width of the new phone

L₁ and W₁ are the length and width of the phone you have now.

I'm sure that if you want to know what the difference is, you can
use that equation to find it.

Concerning the question in the blue box:  I guess "Write an Equation"
was not a very effective strategy for solving this problem.  Not only
did you not write an equation, you didn't even mention that an
equation was supposed to be written when you posted it.  You just
kind of shied away from the whole subject.

Looking over the choices, I'd say that my equation allows you to use
the numbers given in the problem to calculate the unknown.