Question

if a+b=7,a³+b³=133, find a²+b²​

Answer 1

Answer:

29

Step-by-step explanation:

(a+b)^3 = 7^3

a^3 + b^3 + 3ab(a+b) = 343

133 + 3ab(a+b) = 343

3ab(a+b) = 210

3ab(7) = 210

3ab = 30

ab = 10

Now put the value of ab in the 2ab

(a+b)^2 = 7^2

a^2 + b^2 + 2ab = 49

a^2 + b^2 + (2x10) = 49

a^2 + b^2 = 29

Answer 2

Step-by-step explanation:

Step-by-step explanation:

It is simple.

(a+b)3 = a3+b3+3ab(a+b)

343= 133 +3ab(7)

343-133= 7× 3ab

210 = 21ab

So ab = 210/21=10

So (a+b)2 = a2 +b2+ 2ab

49 =a2+b2+ 2ab

49-(2 ×10) =a2+b2

49-20 =29=a2+b2

a2+b2= 29