4X=Y+7,3X+4Y+9=0

3 answers

I DONT UNDERSTAND
You are looking at two linear equations, each represents a straight
line when graphed.

You don't ask what you want done here.
Usual questions are:
- solve the two equations.
- graph the two equations
- find the intersection of the two lines
etc

What about it?
substitute the value of a variable from one equation to the other

4X = Y + 7 ... Y = 4X - 7

substituting ... 3X + 4(4X - 7) + 9 = 0 ... 3X + 16X - 28 + 9 = 0

solve for X , then substitute back to find Y