Question

find the value and plz give me answer​

Answer 1

$\huge{\underline{\underline{\sf{꧁QuEsTiOn꧂}}}}$

find the value of a³+b³ when a+b=4 and ab=5

$\huge{\underline{\underline{\sf{꧁AnSwEr꧂}}}}$

Given,

a+b=4 and ab=5

Squaring both sides,we get,

(a+b)²=(4)²

a²+b²+2ab=16

a²+b²+2×5=16

a²+b²=6

Now (a³+b³)=(a+b)(a²+b²-ab)

(a³+b³)=(4)(6-5)

꧁ a³+b³=4꧂

$\huge{\underline{\underline{\sf{Formula/: used}}}}$

(a+b)²=a²+2ab+b²

(a ³ + b ³) = (a+b)(a²-ab+b²)

Answer 2

Answer:

4

Step-by-step explanation:

Given a+b= 4 ,and a-b =5

apply cube on both sides

(a+b)*3=4*3

a*3+3a*b+3ab*2+b*3=64

a*3+b*3+3ab(a+b)=64

a*3+b*3+3(5)(4)=64

a*3+b*3+60=64

a*3+b*3=64-60

a*3+b*3=4