当a=二分之一,b=三分之二时,求多项式2(2a加3b)的二次方减3(2a加3b)加8(2a加3b)的二次方减7(2a加3b)的值

∵a=1/2,b=2/3
∴2a+3b
=2*1/2+3*2/3
=1+2
=3
∴2(2a+3b)^2-3(2a+3b)+8(2a+3b)^2-7(2a+3b)
=10(2a+3b)^2-10(2a+3b)
=10*3^2-10*3
=10*9-30
=90-30
=60