Question

4x+3y=21;3x+4y=21, then x+y= ?​

Answer 1

Answer:

X + Y =  6

Step-by-step explanation:

4X + 3Y = 21    →  EQUATION 1

3X + 4Y = 21    →  EQUATION 2

6 * (EQUATION 1) - 8 * (EQUATION 2) =

(24X + 18Y = 126) - (24X + 32Y = 168) =

-14Y = - 42

14Y = 42

Y= 3

APPLY VALUE OF Y IN EQUATION 1

4X + 3*3 = 21

4X + 9 = 21

4X = 21 - 9

4X = 12

X = 3

SO, X + Y = 3 + 3 = 6

Answer 2

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