Question

it is known that x+y=10 and that x= z.show that z+y=10

Answer 1

x+y=10
put x=z in it
then
z+y=10

Answer 2

Its very much simple.
let
x+y=10------------#(1)
x=z-----------------#(2)
taking y to left hand side in eqn 1 we get,
x=10-y
now put this in eqn 2,
10-y=z
Now move y to LHS
it becomes, z+y=10
Hence proved.
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