Question

if 3x-2y =18 and xy=5 find the values of 27x^3 - 8y^3​

Answer 1

Answer:

The value of $27x^{3}-8y^{3}$=16779

Step-by-step explanation:

As we have given in the question 2 equations with 2 unknowns

i.e. 1. $3x-2y=18 </strong></p><p><strong>2. xy=5$

From the 2nd equation $x=\dfrac{y}{5}$

Putting this value in equation 1

$\dfrac{3y}{5}-2y=18$

=$3y-10y=90$

=$-7y=90$

=$y=-12.8$

Now for x, We will put the value of y in equation 2

$x=\dfrac{5}{-12.8}$=-0.4

Now putting value of x and y in equation

$27x^{3}-8y^{3}$

$27\times[-0.4]^{3}-8\times[-12.8]^{3}$

$1.728-[-16777.2]=16779$