The gial is to isolate the variable taht is the first thing to remember, second whatever you do to one side you must do to the other. yiu can approach this.in two ways as I see it with 1b or alk fractions. I prefer fractions so first you want yo get rid of the 9/4 on the variabke side so 9/4-9/4 is zero and 7/4-9/4=(-2/4) then you have 1/2b=(-2/4) or (-1/2) so you multipke both sides by two and get b=(-1) hope that helped