Question

plz.. give me a answer

7x +3y 15;12y-5x=39​

Answer 1

Answer:

7x+3y=15 - (i)

12y-5x=39 - (ii)

multiply by 4 in equation no (i)

28x+12y=60 - (iii)

equation (iii) - equation (ii)

12y+28x=60

-12y+5x=-39

33x = 21

x = 21/33

x = 21/33 put in equation no (i)

7(21/33)+3y = 15

3y = 15-147/33

3y = 495-147/33

3y = 348/33

3y = 116/11

y = 116/33. Ans.

Answer 2

Step-by-step explanation:

7x +3y=15 -----[ 1 ]

12y -5x =39

-5x +12y =39

5x - 12y = -39-----[ 2 ]

multiply equ. [ 1 ] by 4

4(7x)+4(3y)=4(-39)

28x+12y= -156 -----[ 3 ]

equ. 3+ equ.2

28x+12y= -156

+ 5x-12y= -39

--------------------------

33x = - 195

x = - 195/33

x = - 65 / 11

x= -65 /11 put the value in the equ. [ 1 ]

7(- 65 / 11 ) + 3y = 15

-455 / 11 + 3y = 15

3y = 15 + 455/ 11

3y = (165+455)/11

3y = 620 / 11

y = 620 / 11×3

y. = 620 / 33

x = -65 / 11

y = 620 / 33