Question

add 6 to both sides to get rid of -6, so that 10g is alone on the left side of the equation.
$5g - 6 = -5g - 4$
$+5g +5g$
$10g - 6 = -4$
$+6 +6$
$square = square$

Explanation:

Step1: Add 6 to left side

$10g - 6 + 6 = 10g$

Step2: Add 6 to right side

$-4 + 6 = 2$

Answer:

Left box: $10g$
Right box: $2$