Question

已知x的平方+2x-2=0,求x的立方+3x的平方+1的值

Answer 1

x^2+2x-2=0

x^2+2x=2

x^3+3x^2+1

=x^3+2x^2+x^2+1

=x(x^2+2x)+x^2+1

=2x+x^2+1

=2+1

=3