Question

18. If 4x +7 y = 9 and 10x +9y = 31 then x - y =​

Answer 1

Answer:

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Step-by-step explanation:

if

4x +7y =9-----(1)

and

10 x+9y=31 -----(2)

by multiplying eq (1) with 10 and eq (2) with 4

we get

40x +70y = 90---(3)

40x +36 y = 124----(4)

by (3) -(4) we get

40x +70y = 90

40x +36 y = 124

- - -

______________

= 34 y = -34

=

$y = \frac{ - 34}{34} \\ y = - 1$

now we got the value of y

substitute this y value in eq (1)

4x +7y =9

4x +7(-1)= 9

4x -7 = 9

4x = 9+7

4x = 16

$x = \frac{16}{4} \\ x = 4$

now we got the value of x

now we have x and y values so

$= x - y = 4 - ( - 1) = 4 + 1 = 5 \\ x - y = 5$

therefore If 4x +7 y = 9 and 10x +9y = 31 then x - y = 5

Answer 2

Answer:

This is your answer

hope it helped