Question

if 3x+5y=90 and 5x+3y=70 then what is the value of x+ y?​

Answer 1

Answer:

Add both the equations

8x + 8y = 160

Divide both side by 8

x + y = 20

Hope this helps you

Answer 2

3x+5y=90 ------- (1)

5x+3y=70 -------(2)

( By elimination process )

(1) × 5

(2) × 3

= 15x+25y=450

= 15x+9y=210

(1) - (2)

15x+25y=450

- 15x-9y= - 210

0x+16y=240

16y = 240

y = 15 ✓

3x+5y=90

3x+75 = 90

3x = 90-75

3x = 15

x = 15/3

x = 5 ✓

x + y = 15+5

x + y =20 ✓✓✓✓✓

HOPE IT IS HELPFUL