Question

плиззз как можно быстрей

Answer 1

a²-b²=(a-b)*(a+b)
1)(38²-28²)/(47²-19²)=(38-28)(38+28)/(47-19)(47+19)=10*66/28*66=10/28=5/14
2)(53²-25²)/(79²-51²)=(53-25)(53+25)/(79-51)(79+51)=28*78/28*130=78/130=39/65
3)(181²-61²)/(319²-77²)=(181-61)(181+61)/(319-77)(319+77) = 120*242/242*396 = 120/396 =10/33
4)(200²-380²)/(420²-160²)=(200-380)(200+380)/(420-160)(420+160)= -180*580/260*580= -180/260=-45/65=-9/13