Question

15x +17y=21, 17x+15y=11 solve the simultaneous equations​

Answer 1

Step-by-step explanation:

15x+17y = 21------------(1)

17x + 15y = 11-----------(2)

_____________

(2)+(1) »

32x + 32y = 32

x+y = 1------------(3)

_____________

15x+17y = 21------------(1)

17x + 15y = 11-----------(2)

_____________

(2)-(1)

» 2x -2y = -10

x- y = - 5 ------------(4)

___________

adding (3)+(4)

x+y = 1

x-y = -5

__________

2x = -4

x = -2

put x = -2 in (3)

-2+ y = 1

y = 3

verification

in (4)

x-y = -2-3 =-5

hence the x and y values are -2 and 3

Answer 2

Answer:

x= 21-17y ÷ 15

17x +15y = 11

17 (21-17y ÷ 15) +15y = 11

357 - 289y ÷ 15 + 15y = 11

357 - 289y +225y = 165

357- 64y = 165

64y = 357 -165

y = 3

x= 21 - 17y ÷ 15

x= 21-17 × 3 ÷ 15

x = -30÷15

x = -2