Question

Si a-b=8 a2 + b2 = 15 Hallar a3 - b3

Answer 1

Respuesta:

saludos...

Explicación paso a paso:

$\begin{bmatrix}a-b=8\\ a\cdot \:2+b\cdot \:2=15\end{bmatrix}\\\\\\\mathrm{Sustituir\:}a=8+b\\\\\\\begin{bmatrix}\left(8+b\right)\cdot \:2+b\cdot \:2=15\end{bmatrix}\\\\\\\begin{bmatrix}16+4b=15\end{bmatrix}\\\\\\a=8-\frac{1}{4}\\\\\\a=\frac{31}{4}\\\\\\a=\frac{31}{4},\:b=-\frac{1}{4}$

OjO Hallar a3-b3

$\frac{31}{4}\left(3\right)-\left(-\frac{1}{4}\right)\left(3\right)\\\\\\=\frac{93}{4}-\left(-\frac{1}{4}\right)\left(3\right)\\\\\\=\frac{93}{4}-\left(-\frac{3}{4}\right)\\\\\\=24$