Question

Solve the following pair of linear equations by the substitution method. 0 . 5 x + 0.2 y = 1.5 and 0. 4 x + 0 . 7 y = − 1 . 5 find x and y​

Answer 1

Answer:

ANSWER

7x+11y=0                   ......(i)

3x−5y=0                      ......(ii)

On multiplying equation (i) by 3 and equation (ii) by 7. we get,

21x+33y=0          ......(iii)

21x−35y=0           ......(iv)

On subtracting equation (iv) from equation (iii). we get,

21x+33y=0        

−21x−+35y=−0

(33+35)y=0          

⇒y=0

On substituting y=0 in equation (i). we get,

7x+11×0=0

⇒7

Answer 2

Answer:

Step-by-step explanation:

if you have problem with decimal,then multiply both the equation by 10

5x+2y=15  and 4x+7y=-15

now 5x=15-2y or x=15-2y/5 or  x=3-2y/5

in eq2   4(3-2y/5)+7y=-15

      12-8y/5 +7y=15

        (60-8y+35y)/5=15   lcm

         -8y+35y+60=15*5

        27y=75-60

           y=15/27 =5/9 or 0.5

put value of y in eq

x=3-(2/5*5/9)

x=3-2/9  = 25/9 or 2.8