If 9,x,x and 49 are in proportion, find the value of x.
14
35
7
21
Given: 9,x,x,49 are in proportion i.e. 9:x::x:49 ⇒9x=x49 ⇒x×x=9×49 ⇒x×x=441 ⇒x×x=21×21 ⇒x=21
If 3x−7y=10 and xy=−1, find the value of 9x2+49y2
If 9, x, x and 49 are in proportion, find the value of x.