we have that
y = 3x + 5
and that
z = x² + 2x - 5
we want to know what yz or y·z is equal to
we have what y and z are equal to so we can multiply them together
(3x+5)(x²+2x-5)
first we multiply each value in the second set of parentheses by 3x and then multiply each value in the second set of parentheses by 5 and then combine like terms.
(3x+5)(x²+2x-5)
3x³+6x²-15x + 5x² +10x -25
3x³ + 11x² -5x -25
so your answer should be
D) 3x³+11x²-5x-25