The numbers going to the left on a number line means the values are smaller and the numbers going to the right means the values are bigger.
Take the value '0' for example, the value on the right of zero is '1', which is a value bigger than zero, and the value to the left of '0' is '-1', which is a value smaller than zero.
Factoring <span> b2-4b+4</span> The first term is, <span> <span>b2</span> </span> its coefficient is <span> 1 </span>. The middle term is, <span> -4b </span> its coefficient is <span> -4 </span>. The last term, "the constant", is <span> +4 </span>
Step-1 : Multiply the coefficient of the first term by the constant <span> 1 • 4 = 4</span>
Step-2 : Find two factors of 4 whose sum equals the coefficient of the middle term, which is <span> -4 </span>. <span><span> </span></span>
Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -2 and -2 <span>b2 - 2b</span> - 2b - 4
Step-4 : Add up the first 2 terms, pulling out like factors : b • (b-2) Add up the last 2 terms, pulling out common factors : 2 • (b-2) Step-5 : Add up the four terms of step 4 : (b-2) • (b-2) Which is the desired factorization