Question

Dacă a × b = -2/5 și a × c = 1/3
A) a × ( b + c ) =
B) a × ( b - c ) =
???? Va rag...rapid!!!!

Answer 1

$a \cdot b = -\frac{2}{5}$
$a \cdot c = \frac{1}{3}$
$A) a \cdot (b+c) = ab + ac = -\frac{2}{5} + \frac{1}{3} = \frac{-6+5}{15} = \frac{-1}{15}$
$B) a \cdot (b-c) = ab - ac = -\frac{2}{5} - \frac{1}{3} = \frac{-6-5}{15} = \frac{-11}{15}$