Question

5. The value of 64a-125b, if 4a-5b=2 and ab =6​

Answer 1

Explanation:

ab= 6

a= 6/b

4a-5b= 2

4×6/b-5b=2

24/b-5b=2

24-5b²=2b

5b²+2b-24=0

d=b²-4ac

d=4+480

d=484

b=-2+-22/10

b= 2or -24/10

a=3or10/-4

so 64×3-125×2

192-250

-58