(1)2x^2+3x(2)3x^2+4x=3(3)2x^2-5x+3=0(4)4x^2+25=20x

(1)2x^2+3x(2)3x^2+4x=3(3)2x^2-5x+3=0(4)4x^2+25=20x

(1)2x^2+3x=0 ?x(2x+3)=0x₁=0、x₂=-3/2(2)3x^2+4x=3 3x²+4x-3=0Δ=16+36=52x=(-4±√52)/6(3)2x^2-5x+3=0(x-1)(2x-3)=0x₁=1、x₂=3/2(4)4x^2+25=20x 4x²-20x+25=0 (2x-5)²=...

Observe the number in the following column and fill in the nth number on the horizontal line according to some rule (algebraic formula containing N, n = 1, 2, 3...), 2, 6, 10, 14, 18_____ ...
Hurry up, OK, 5 more points!!!!!!!!

2,6,10,14,18…… 4n-2

One column number: 0, - 1, 3, - 6, 10, - 15, 21 According to this rule, the nth number is______ ．

The nth number is 0 + 1 + 2 + 3 + +(n-1) = n (n − 1) 2, the sign is (- 1) n-1, so the nth number is (- 1) n-1n (n − 1) 2