<span>d=(An-Ak)/(n-k)</span><span>d=7/1=7</span><span>An=A1+(n-1)*d</span>а)156=2+(n-1)*7<span></span>156-2=7n-7
1) d¹⁸⁰=(d¹²)¹⁵
2) ((a-8)¹³)¹⁰=(a-8)¹³⁰.