Zachary purchased a computer for $1 comma 300 on a payment plan. two months after he purchased the computer, his balance was $1 comma 040. six months after he purchased the computer, his balance was $520. what is an equation that models the balance y after x months? the equation nothing models the balance y after x months. (type your answer in slope-intercept form. use integers or fractions for any numbers in the equation. do not include the $ symbol in your answer.)