Coefficients are the numbers before a variable, meaning that 7 and -4 (be careful of that subtraction sign) are the coefficients. Additionally if you were asked what the leading coefficient was the answer would be 7 because it has the greatest exponent attached to it (2).
42300 / 10 = 4230 4230 * 500 = 2115000 a number multiplied by ten equals to 42300, so 10a = 42300, then a = 4230, then you multiply 4230 and 500 together, which gives you 2115000
