"What if I bring in zero pair?"
"If I have 2 positive x's and 2 negative x's that equals zero. But the equation says -2x. So that means I have to add 2 more reds."
"What if I bring in zero pair?"
"If I have 2 positive x's and 2 negative x's that equals zero. But the equation says -2x. So that means I have to add 2 more reds."