x + 100 - ( 4 x 45 ) = 320

x + 100 - 180 = 320

x + 100 = 320 + 180

x + 100 = 500

x = 500 - 100

x = 400

1) \(=a^3+b^3+c^3+3\left(a+b\right)\left(b+c\right)\left(c+a\right)-a^3-b^3-c^3\)

\(=3\left(a+b\right)\left(b+c\right)\left(c+a\right)\)