Question

Find the value of 27x³+64y³+36xy(3x+4y), when x=5 and y=-3​

Answer 1

Answer:

==> 27x³+64y³+36xy(3x+4y)

==> (3x)³+(4y)³+3.3x.4y(3x+4y)

we know that formula of (x+y)³ = x³+y³+3xy(x+y)

so according to question, x = 3x , y = 4y

so, (3x+4y)³

given => x = 5 ; y = -3

==> [3(5) + 4(-3)]³

==> [15 - 12]³

==> [3]³

==> 27

answer = 27

Answer 2

Answer:

27.5.5.5+ 64.-3.-3.-3+ 36.5.-3(3.5+4.-3)

3375+64.9.-3+(-540)(27)

3375+1728-540(27)

4563(27)

123201