0 Deepak BoraNewbie Asked: July 15, 20202020-07-15T16:44:32+05:30 2020-07-15T16:44:32+05:30In: ICSE if (4x^2 + xy ) : (3xy – y^2) = 12 : 5 ,find (x+2y) : (2x+7) 0 Ration and proportion questionratio and proportion Share Facebook 1 Answer Voted Oldest Recent Deepak Bora Newbie 2020-07-16T00:50:27+05:30Added an answer on July 16, 2020 at 12:50 am (4x² + xy )/(3xy – y²) = 12/ 5 cross multiplying 5(4x²+xy) = 12(3xy-y²) 20x² + 5xy = 36xy- 12y² divide complete equation by xy 20x/y +5 = 36 – 12y/x 20x/y + 12y/x = 36-5 20x/y +12 y/x = 31 let x/y = a ∴ 20a+ 12/a = 31 ∴ 20a² – 31a + 12 = 0 20a² -16a-15a+ 12 = 0 4a(5a-4)-3(5a-4)=0 (5a-4)(4a-3)= 0 ∴ a= 4/5 & a= 3/4 because x/y = a ∴ x/y =4/5 & x/y =3/4 0 Reply Share Share Share on Facebook Share on Twitter Share on LinkedIn Share on WhatsApp Leave an answerLeave an answerCancel reply Featured image Select file Browse Add a Video to describe the problem better. Video type Youtube Vimeo Dailymotion Facebook Choose from here the video type. Video ID Put Video ID here: https://www.youtube.com/watch?v=sdUUx5FdySs Ex: "sdUUx5FdySs". Click on image to update the captcha. Visual Text Save my name, email, and website in this browser for the next time I comment. Related Questions Using the properties of proportion, solve the following equation for x; given x³+3x/3x²+1=341/91 Give x³+12x/(6x²+8) =(y³+27y/9y²+27). Using componendo and dividendo find x : y. Given that a³+3ab²/(b³+3a²b) =63/62. Using componendo and dividendo find a: b. Given x=root(a2+b2) +root(a2−b2) /(root (a2+b2) −root(a2−b2) Use componendo and dividendo to prove that b²=2a²x/x²+1 If x=root(a+x) +root(a−1) /root(a+1) −root(a−1) , using properties of proportion , show that x² – 2ax + 1 ...
(4x² + xy )/(3xy – y²) = 12/ 5
cross multiplying
5(4x²+xy) = 12(3xy-y²)
20x² + 5xy = 36xy- 12y²
divide complete equation by xy
20x/y +5 = 36 – 12y/x
20x/y + 12y/x = 36-5
20x/y +12 y/x = 31
let x/y = a
∴ 20a+ 12/a = 31
∴ 20a² – 31a + 12 = 0
20a² -16a-15a+ 12 = 0
4a(5a-4)-3(5a-4)=0
(5a-4)(4a-3)= 0
∴ a= 4/5 & a= 3/4
because x/y = a
∴ x/y =4/5 & x/y =3/4