解答题已知x1,x2是方程2x^2-8x+5=0的两根,不解方程,求下列各式的值(x1+1)(x2+1)
x1+x2＝4
x1*x2＝5/2
(x1+1)(x2+1)＝x1*x2+x1+x2+1
＝4+5/2+1＝7.5