Question

If a + 2b = 5; then show that:
a³ + 8b³ + 30ab =125



​

Answer 1

Answer:

2b =5 ok than subtract a3 + 8b3

Answer 2

Answer:

Step-by-step explanation:

Given a+2b = 5 ----(1)

To prove:   a³+8b³+30ab=125

On cubeing equation (1) , we get

(a+2b)³ = 5³

=> a³+(2b)³+3×a×2b×(a+2b)=125

we know the algebraic identity:

=> a³+8y³+6ab×5 = 125

From equation (1) , we get */

=> a³+8y³+30ab = 125

hope it's help you