Question

how to substitute this x+y=16 x=7-5y

Answer 1

really you just put your stuff for x in the equation and solve it you have to. since it is x + y = 16. the equations after you substitute it would be 7-5y+y = 16 then you can solve for y from there by combining like terms and blah blah

Answer 2

can you show me the steps please

Answer 3

x = 16-y
Put that in the other equation (solve it in terms of y)
16-y = 7-5y
9 = -4y
y = -9/4
Then put that back in the original equation
x = 16-9/4
x = 55/4