Let $a=-1$, let $b=3$, and let $c=-5$. Calculate $b (abc+5ab) + b (c+a) $.

Answer: $b (abc+5ab) + b (c+a) $ = - 18

Step-by-step explanation:

If $a = $ - 1, $b = $3 and $c = $ - 5, then

abc = - 1 * 3 * - 5 = 15

5ab = 5 * - 1 * 3 = - 15

Then,

$b (abc+5ab) = 3 (15 - 15)

Opening the brackets, it becomes

3 * 0 = 0

(c + a) $ = - 5 - 1 = - 6

Then,

b (c+a) $ = 3 * - 6 = - 18

Therefore,

$b (abc+5ab) + b (c+a) $ = 0 + ( - 18)

$b (abc+5ab) + b (c+a) $ = 0 - 18 = - 18