Your local radio station is having their yearly music player and concert ticket giveaway. For one minute, every 5^\text{th}5 th 5, start superscript, start text, t, h, end text, end superscript caller will win a music player and every 7^\text{th}7 th 7, start superscript, start text, t, h, end text, end superscript caller will win concert tickets. You were just the first caller to win both a music player and concert tickets! What number caller were you? What is the coefficient in the expression 10x+ 810x+810, x, plus, 8?