Answer:
[tex]-420[/tex]
Explanation:
if we call the fist of the numbers [tex]x[/tex], then the following number is [tex]x+1[/tex].
the product of this two numbers according to the problem is:
[tex](x)(x+1)=420[/tex]
which results in:
[tex]x^2+x=420[/tex]
The standar form of a quadratic equation is
[tex]Ax^2+Bx+C=0[/tex]
so we must make the equation equal to zero: [tex]x^2+x-420=0[/tex]
and this way we can see that the constant [tex]C[/tex] in the quadratic expression is [tex]-420[/tex].
if you want the values of the consecutive numbers, they are 20 and 21.