Answer:
600
Step-by-step explanation:
Note that the expansion of
(a + b)(c + d) = ac + ad + bc + bd, hence
ac + ad + bc + bd = 20 × 30 = 600
so
[tex]ac + ad + bc + bd[/tex]
It can be simplified using the distributive property since "ac+ad" have a common factor of "a" and "bc+bd" have a common factor of "b" which makes it
[tex](ac + ad) + (bc + bd)[/tex]
[tex]a(c + d) + b(c + d)[/tex]
and since "a(c+d) + b(c+d)" have a common factor of "(c+d)" we can use the distributive property which makes it
[tex](a + b)(c + d)[/tex]
plug in "a+b" for 20 and "c+d" for 30 and we get
[tex](20)(30)[/tex]
[tex]600[/tex]
