Question

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Explanation:

Step1: Aplicar propiedad distributiva (b)

Se usa $a(b+c) = ab + ac$, así que $7(x+3) = (7 \times x) + (7 \times 3)$

Step2: Aplicar propiedad distributiva inversa (d)

Se usa $ab + ac = a(b+c)$, así que $(x \times 4) + (x \times 5) = x(4+5)$

Answer:

b. $7(x + 3) = (7 \times \boldsymbol{x}) + (\boldsymbol{7} \times 3)$
d. $(x \times 4) + (x \times 5) = \boldsymbol{x}(4 + 5)$