Question

write the value of x+y for the equations 8x-7y=11 and 7x-8y=4​

Answer 1

Step-by-step explanation:

Here,

8x-7y=11

8x= 11+7y

x= (11+7y)/8 (1)

Now putting the value of x in next equation

we have

7x-8y=4

7(11+7y)/8 -8y= 4

(77+49y-64y)/8= 4

-15y= 32-77

-15y= -45

y= 45/15= 3

therefore x= (11+7y)/8=(11+7×3)/8= (11+21)/8= (32)/8= 4

x+y= 3+4= 7