Question

(2x十1)²—(x十3)²—(x一1)²十1

Answer 1

〔2x+1〕²-〔x+3〕²-〔x-1〕²+1

=4x²+4X+1-（x²+6X+9）-（x²-2X+1）+1

=4x²+4X+1-x²-6X-9-x²+2X-1+1

=（4-1-1）x²+（4-6+2）X+1-9-1+1

=2x²-8