展开 (x+3)(x+!)

解答

展开

(x + 3) (x +!)

! x^{2} + 3! x

求解步骤

(x + 3) (x +!)

= (x + 3) (+! x)

使用分配律:

a (b + c) = ab + a c

a = (x +!), b = x, c = 3

= (x +!) x + (x +!) \cdot 3

= x (+! x) + 3 (+! x)

化简

x (+! x) + 3 (+! x) :! x^{2} + 3! x

=! x^{2} + 3! x

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