Question

the factorization of 3x + 15 z is​

Answer 1

Answer:

Assuming you mean "3x + 15":The common factor is 3. That's one factor of the expression. Divide each part by 3, to get the other factor.

Answer 2

Answer:

z = -x-y (given)

z^3 = -x^3 - 3x^2y -3xy^2 - y^3 (binomial expansion)

x^3 + y^3 + z^3 = 90 (given)

-3x^2y -3xy^2 = 90 (by substitution)

x^2y + xy^2 = -30

xy (x + y) = -30

Then an easy search (guess and check) through the factors of -30 gives us xy = -15 and x + y = 2.

x = 5 and y = -3

z= -x-y = -2

And then xyz = 30.