Question

Study the graph given below. Choose the equation whose graph is given:
(i) y = x
(ii) y = 2x
(iii) y = 2x + 1
(iv) x + y = 0

Answer 1

(iii) y = 2x + 1

The two given points are $A(1,3),B(-1,-1)$.
These points must satisfy the equation in order to form the graph.
Let $y=2x+1$ be the equation of this graph.
At $A(1,3)$, $LHS=3,RHS=2x+1=2\times 1+1=3$
So, $LHS=RHS$
Now, at $B(-1,-1)$, $LHS=-1,RHS=2x+1=2\times (-1)+1=-1$
So, $LHS=RHS$
Hence, the given points satisfy this equation.
Hence, $y=2x+1$ is the equation of the graph.