Question

I don't know how my teacher got from 990/4 to 495/2

Answer 1

The teacher reduced the fraction.

You can reduce a fraction by dividing the numerator and the denominator by the same number.

990 and 4 are both even numbers. They are both divisible by 2.
990/2 = 495

4/2 = 2

990/4 = 495/2

$log (4x + 10) = 3$

$log_b x = y ~~means~~ b^y = x$

$4x + 10 = 10^3$

$4x + 10 = 1000$

$4x = 990$

$x = \dfrac{990}{4}$

$x = \dfrac{495 \times 2}{2 \times 2}$

$x = \dfrac{495}{2} \times \dfrac{2}{2}$

$x = \dfrac{495}{2} \times 1$

$x = \dfrac{495}{2}$