Which expression is the factorization of x2 + 10x + 21?

The factorization of the given expression [tex]\rm x^2+10x+21[/tex] is (x+3)(x+7) the option first is correct.It is given that the expression [tex]\rm x^2+10x+21[/tex]It is required to find which expression is the factorization of the given expression, the options are:a) (x + 3)(x + 7)b) (x + 4)(x + 6)c) (x + 6)(x + 15)d) (x + 7)(x + 14)What is polynomial?Polynomial is the combination of variables and constants in a systematic manner with "n" number of power in ascending or descending order.We have an expression:[tex]\rm x^2+10x+21[/tex][tex]\rm x^2+7x+3x+21[/tex]  Breaking 10x into 7x and 3x because the multiplication of 7x and 3x is [tex]\rm 21x^2[/tex] and the addition is 10x.[tex]\rm x^2+7x+3x+21\\\\\rm x(x+7)+3(x+7)\\\\\rm (x+7)(x+3)[/tex]or[tex]\rm (x+3)(x+7)[/tex]Thus, the factorization of the given expression [tex]\rm x^2+10x+21[/tex] is (x+3)(x+7) the option first is correct.Learn more about Polynomial here:brainly.com/question/17822016