Question

solve the equation for X and Y : 7x equal to 8y+11 and 8x -7y -7 equal 0​

Answer 1

Step-by-step explanation:

7x = 8y + 11

7x - 8y = 11 equ (1)

8x - 7y - 7 = 0

8x - 7y = 7 equ (2)

multiply equ 1 with 8 and equ 2 with 7

8 ( 7x - 8y = 11)

42x - 64y = 88 equ (3)

7(8x - 7y = 7)

42x - 49y = 49. equ (4)

subtract equ (3) - equ (4)

42x - 64y = 88

- (42x - 49y = 49)

42x - 64y = 88

- 42x + 49y = - 49

- 15y = 39

y = - 39/15

7x = 8y + 11

x = (8y + 11)/7

substitute y value in the above equation

$x = \frac{8y + 11}{7} \\ x = \frac{(8 \times - \frac{39}{15} )+ 11 }{7} \\ x = \frac{ \frac{ - 312}{15} + 11 }{7} \\ x = \frac{ \frac{ - 312 + 165}{15} }{7} \\ x = \frac{ \frac{ - 147}{15} }{7} \\ x = \frac{ - 147}{15} \times \frac{7}{1} \\ x = \frac{ - 1029}{15}$

Hope you get your answer