Yvonne is thinking of a number. fifty, decreased by three times the number, is the same as seven times the number, increased by 80. what is yvonnes number

If x (a number) : 50-3x=7x-80
add 80 to each side and add 3x to the other side to get the right variables on the right side. Now your equation should look like this: 10x=130 then divide both sides by 10 10 to get Yvonnes number which is 13.