cosC=(a^2+b^2-c^2)/(2ab)
=(4+9-7)/(2*2*3)
=6/12=1/2
∵C0
sinC=√(1-cos^2C)=√3/2
S△ABC=1/2*a*bsinC=1/2*2*3*√3/2=3√3/2