Question

if a square + 9 upon a square = 31 what is the value of a- 3 upon a​

Answer 1

Step-by-step explanation:

Given:

${a}^{2} + \frac{9}{ {a}^{2} } = 31\\we\: have\\ (a-\frac{3}{a})^2 = a^2 +\frac{9}{a^2}-2 \times a \times \frac{3}{a} \\(a-\frac{3}{a})^2=31-6\\(a-\frac{3}{a})^2=25 \\(a-\frac{3}{a})= \pm 5$