Question

Find the values of ( x + y ) and (x - y) if, 3x + 4y = 11; 4x + 3y = 10​

Answer 1

Step-by-step explanation:

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Answer 2

Step-by-step explanation:

$3x + 4y = 11 \: \: \: \: ....(1) \\ 4x + 3y = 10 \: \: \: \: ....(2) \\ \\ multiply \: {eq}^{n} \: (1) \: by \: 4 \: and \: multiply \: {eq}^{n} (2) \: by \: 3 \\ and \: then \: substract\\ \\ 4(3x + 4y) - 3(4x + 3y) = 4 \times 11 - 3 \times 10 \\ 12x + 16y - 12x - 9y = 44 - 30 \\ 7y = 14 \\ y = \frac{14}{7} = 2 \\ y = 2 \\ \\ putting \: y = 2 \: in \: {eq}^{n} (1) \\ 3x + 4(2) = 11 \\ 3x = 11 - 8 \\ 3x = 3 \\ x = \frac{3}{3} = 1 \\ x = 1 \\ then \\ x + y = 1 + 2 = 3 \\ x - y = 1 - 2 = - 1$