Question

( begin{aligned} 9+2 b &=3 a^{2}+a b^{2}+2 times 2 b times c &=9 a^{2}+9 b^{2} &=9-9 text { ba } &=9-9 times-5 &=29 end{aligned} )
( (4) quad(a+2 b)=3 )
( (a+2 b)^{3}=8.27 )
( a^{3}+8 b^{3}+3 times 9 times 2 b cdot(9+2 b)=27 )
( a^{3}+8 b^{3}+3 times 2 times-5(3)=27 )
( a^{3}+8 b^{3}=27+90 )
( =117 )

# If a + 2b = 3 and ab = -5, then find the value of (1) a2 + 462 (ii) a3 + 863

Solution