Question

2x + y = 9 .................. (i)
x + 2y = 21 .................. (ii)

Answer 1

Answer:

2x+y=9........(1)

x+2y=21.....(2)

multiply by 2 in equation(1) , we get

4x+2y=18......(3)

subtract equation (3)by(2), we get

x+2y=21

-4x+2y=18

(+). (-). (-)

5x=3

x=3/5

the value of x put in equation (1), we get

2×3/5+y=9

6/5+y=9

y=9-6/5

y=45-6/5

y=39/5

the value of x is 3/5 and y is 39/5

Answer 2

GIVEN EQUATIONS:

$2x + y = 9.....(1) \\ x + 2y = 21.....(2)$

NOW:

$2x + y = 9 \\ y = 9 - 2x......(3)$

PUT THE Y VALUE IN THE EQ.2

$x + 2(9 - 2x) = 21 \\ x + 18 - 4x = 21 \\ - 3x = 21 - 18 \\ - 3x = 3 \\ x = \frac{3}{ - 3} \\ x = - 1$

PUT THE X VALUE IN THE EQ.3

$y = 9 - 2x \\ y = 9 - 2( - 1) \\ y = 9 + 2 \\ y = 11$

FOR VERIFICATION PUT BOTH VALUES IN THE EQUATIONS 1&2

$2x + y = 9 \\ 2(- 1 )+ 11 = 9 \\ - 2 + 11 = 9 \\ 9 = 9$

$x + 2y = 21 \\ - 1 + 2(11) = 21 \\ - 1 + 22 = 21 \\ 21 = 21.$

MARK BRAINLIEST.