Question

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

11th - 12th Class

Maths

Solution

201

4.0 (1 ratings)

( 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 )