Question

63=3n+1/2n(n-1)2得n²+2n-63=0求详细过程

Answer 1

∵63=3n+(1/2)n(n-1)2.∴63=3n+(1/2)×2n(n-1) ; ---------乘法交换律63=3n+n(n-1); ---------同级运算从左往右依次运算63=3n+n²-n; 63=2n+n².故0=n²+2n-63,即n²+2n-63=0.(n+9)(n-7)=0.可得:n=-...