Question

va rog dau coroana ​

Answer 1

Explicație pas cu pas:

a=1 /1+2+...+10= 1/55

1+2+...+10=10×11 /2=55

b=1/ 1+2+3+...+11=1/66

1+2+3+...+11=11×12 /2=66

a)b‐¹= inversul lui b=55/1=55

b)a:b= 1/55: 1/66= 1/55×66/1=66/55=6/5

c)-11(a-b)= -11(1/55-1/66)= (-11×1/55)-(-11×1/66)= –1/5–(–1/6)= –1/5+1/6= –6/30+5/30= –1/30

d)22×(5a-6b)= 22( 5×1/55-6×1/66)= 22(1/11-1/11)=22×0=0