Solve the simultaneous equations using graph method (x + y=2).(x _y=4) make y the subject of the formula for number a x+y=2

• If $x = 0$, then $y = 2$. Point: $(0, 2)$.
• If $y = 0$, then $x = 2$. Point: $(2, 0)$. These points define the first line.

• If $x = 0$, then $-y = 4 \implies y = -4$. Point: $(0, -4)$.
• If $y = 0$, then $x = 4$. Point: $(4, 0)$. These points define the second line.

When these two lines are plotted on a graph, their intersection point is the solution. From the graph, the lines intersect at $(3, -1)$.

Substitute $x=3$ and $y=-1$ into both original equations:

• For $x + y = 2$: $3 + (-1) = 2 \implies 2 = 2$ (True)
• For $x - y = 4$: $3 - (-1) = 4 \implies 3 + 1 = 4 \implies 4 = 4$ (True) Both equations are satisfied.

The solution to the simultaneous equations is:

The solution is $\boxed{x=3, y=-1}$.

So, $y$ as the subject of the formula is: