Aprēķins: 21QBGT - 1
a_n =
a1+ d* (n-1)
a1+ d* (n-1)
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a_n = a1+ d* (n-1)$$a_{n}$$ = $$a1+d\cdot (n-1)$$
a1+ d* (n-1) = a_n$$a1+d\cdot (n-1)$$ = $$a_{n}$$
a1 = a_n- d* (n-1)$$a1$$ = $$a_{n}-d\cdot (n-1)$$
a1 = a_n- n* d+d$$a1$$ = $$a_{n}-n\cdot d+d$$
a1 = a_n- 6* 1.5+1.5$$a1$$ = $$a_{n}-6\cdot 1.5+1.5$$
a1 = a_n-9+1.5$$a1$$ = $$a_{n}-9+1.5$$
a1 = a_n-7.5$$a1$$ = $$a_{n}-7.5$$