First of all, you need to memorize several forms of the equation of a straight line. Here you have -2y - 2x = -6 in "standard form" and want the equivalent equation in "slope intercept form," y = mx + b.
To get this, solve the first equation for y by dividing all three terms by -2:
y + x = 3.
Then solve this result for y:
y = -x + 3
This is the desired equation in slope-intercept form.
