Question 13887
x+y=1
3x+4y=1
Is all that means, is one equation is solved for one variable and substituted into the other equatioon to solve that equation.
First you need to find out what x or y =, lets take the first equation(since it would the easier one to solve).
x+y=1
x=-y+1
Now we substitute that answer for x in the equation;
3(-y+1)+4y=1
-3y+3+4y=1
y+3=1
y=-2
Now we have what y= , now we can solve for x;
3x+4(-2)=1
3x-8=1
3x=9
x=3
Hope you understand
=)