Question

1.5x+2.4y=1.8;2.5(x+1)=7y have solution as

Answer 1

I want to show you a good method to solve these equations.  Take time to read it and follow it.  This is the method in the International standards.  It is easy when you understand it.

  1.5  x  + 2.4 y  -  1.8  =  0
  2.5  x  -  7 y   + 2.5   =  0

For solving :  a x + b y + c  =  0     and    d x + e y + f  = 0 ,  we do as mentioned in the diagram enclosed.  This is the easier way.

   -1.8      1.5      2.4      -1.8

   2.5      2.5        -7       2.5
         y                    x

x =   (-7*-1.8  -  2.4*2.5 ) / (2.5 * 2.4  - 1.5*-7)
   = (12.6  -  6) / (6 + 10.5)  =  6.6/16.5 =  0.40  = 2/5
 
y =  (2.5*1.5 -  -1.8*2.5) / (2.5*2.4 - 1.5*-7)
   = (3.75 + 4.5) / 16.5    =  8.25 / 16.5  = 0.50  = 1/2