Question

A+b=20 c+d=30 Calculati ac+ad+bc+bd= ?

Answer 1

600

Explanation:

Note that the expansion of

(a + b)(c + d) = ac + ad + bc + bd, hence

ac + ad + bc + bd = 20 × 30 = 600

Answer 2

so

`ac + ad + bc + bd`

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

`(ac + ad) + (bc + bd)`

`a(c + d) + b(c + d)`

and since "a(c+d) + b(c+d)" have a common factor of "(c+d)" we can use the distributive property which makes it

`(a + b)(c + d)`

plug in "a+b" for 20 and "c+d" for 30 and we get

`(20)(30)`

`600`