(1+19/105)+(1+19/105*2)+(1+19/105*3)+...+(1+19/105*20)简算
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![(1+19/105)+(1+19/105*2)+(1+19/105*3)+...+(1+19/105*20)简算](/uploads/image/z/33778-10-8.jpg?t=%EF%BC%881%2B19%2F105%EF%BC%89%2B%EF%BC%881%2B19%2F105%2A2%EF%BC%89%2B%EF%BC%881%2B19%2F105%2A3%EF%BC%89%2B...%2B%EF%BC%881%2B19%2F105%2A20%EF%BC%89%E7%AE%80%E7%AE%97)
(1+19/105)+(1+19/105*2)+(1+19/105*3)+...+(1+19/105*20)简算
(1+19/105)+(1+19/105*2)+(1+19/105*3)+...+(1+19/105*20)简算
(1+19/105)+(1+19/105*2)+(1+19/105*3)+...+(1+19/105*20)简算
=1+1+……+1+19/105*(1+2+……+20)
=1*20+19/105*20*21/2
=20+19/105*210
=20+38
=58
2x^2-6x+3=
=2x^2-6x+2+1
=2(x^2-3x+1)+1
=2×0+1
=1边长4/9÷4=1/9米
面积1/9×1/9=1/81平方米
两边乘6
12x-3x+3=4x+12
9x-4x=12-3
5x=9
x=9/5