Question

6 + 8/10x = 9/10x what is x?

Answer 1

6+8/10x=9/10x
subtract 8/10x from both sides
6=1/10x
multiply each side by 10
60=x

Answer 2

$\sf 6+ \frac{8}{10} x= \frac{9}{10} x$
Subtract $\frac{8}{10} x$ from both sides

$\sf 6+ \frac{8}{10} x - \frac{8}{10} x= \frac{9}{10} x- \frac{8}{10} x$

Simplify:
$\sf 6 = \frac{1}{10}x$

Multiply 10 on both sides:
$\sf 6 \times 10= \frac{1}{10}x \times 10$

Simplify
$\sf 60= x$

So your answer is x=60. :)