Question

a-b=7,ab=18 then a³-b³=​

Answer 1

this solution is based on class 10th

a=7+b ......1

and in ab=18

a=18/b. .....2

eq.1 and 2 are equal

7+b=18/b

b^2+7b-18=0

b=-b+-√(b)²-4ac/2a

b=-7+-√49-4(1)(-18)/2×1

b=-7+-11/2

b=-7+11/2. ,. b=-7-11/2

b=2,-9

we reject -9 Because it is negative

b=2

but it in a-b=7

a-2=7

A=9

a³-b³=?

(9)³-(2)³=?

729-8=?

721 is the answer