Срочно помогите пожалуйста)711 и 712

Решите задачу:

$1) 1.2 ^{2} =1.44 \\ 0.68 ^{2} =0.4524 \\ 7.2 ^{2} =51.84 \\ 2.7 ^{2} =7.29 \\ 0.89 ^{2} =0.7921 \\ 0.47 ^{2} =0.2209 \\ \\ 2) \sqrt{8.41} =2.9 \\ \sqrt{67.24}=8.2 \\ \sqrt{0.3136} =0.56 \\ \sqrt{0.5776}=0.76 \\ \\$

$712 \\ 1)6.4 ^{2} -4.4 ^{2} =40.96-19.36=21.6 \\ 2) (3.9-2.5) ^{2} =1.4 ^{2} =1.96 \\ 3)(3.9+2.5) ^{2} =6.4 ^{2} =40.96 \\ \\ 4)6.4 ^{2} -4.4 ^{2} =(6.4-4.4)(6.4+4.4)=2*10.8=21.6 \\ 5) 3.9 ^{2} -2*3.9*2.5+2.5 ^{2} =15.21-19.5+6.25=1.96 \\ 6)3.9 ^{2} +2*3.9*2.5+2.5 ^{2} =15.21+19.5+6.25=40.96$