22000=15000(1+.089/4)^4t 22/15=(1.02225)^4t log(22/15)=4tlog1.02225 (log(22/15)/4log1.02225)=t (.16633/.038228)=t t=4.35 years or 4 years and approximately 4 months
X=9.51 or x=-1.01 (to 3 sf) if you want exact value just continue from where i left off from the pic :) its the quadratic formula i think thats the name of it