A straight-line graph has the form $y = mx + c$, where $m$ is the gradient and $c$ is the y-intercept.
To find a point, substitute $x$. For $y = 2x + 1$, when $x = 3$, $y = 2(3) + 1 = 7$. The line $y = 4x + 1$ has gradient 4 and crosses the $y$-axis at 1.
Remember
- $y = mx + c$: $m$ = gradient, $c$ = y-intercept.
- Substitute an $x$-value to find its $y$-value.