Question 260447
5N+7N=12N
2*5N+2*7N=96
10N+14N=96
24N=96
N=96/24
N=4 ANS. FOR THE MULTIPLIER
5*4=20 ANS. FOR ONE SIDE
7*4=28 ANS. FOR THE OTHER SIDE 
PROOF
2*20+2*28=96
40+56=96
96=96
20*28=560 cm^2 is the area.