Sir please give me a detailed solution of this question as it was already asked in various important examinations in which we have given two equations x/6+y/15=4, x/3-y/12=19/4 and we have to find the value of variables x and y by using the method of cross multiplication
RS Aggarwal, Class 10, chapter 3C, question no 8
Simplify given equations:
x/6+y/15=4
(5x+2y)/30=4
5x+2y−120=0
And x/3−y/12=19/4
4x−y−57=0
New set of equation is:
5x+2y−120=0....(1)
4x−y−57=0....(2)
From equation (1):a1=5,b1=2 and c1=−120
From equation (2):a2=4,b2=−1 and c2=−57
Using cross multiplication
x/(−114−120)=y/(−480+285)=1/(−5−8)
x/−234=y/−195=1/−13
x/−234=1/−13⇒x=−234/-13
⇒x=18
And
y/−195=1/−13
Or y=15
Answer x=18 and y=15