Lesson-3.1.5- Interpret and obtain the equation of a straight-line graph. Questions may: ??? use and request lines in different forms, e.g. ax + by = c y = mx + c x = k ??? involve finding the equation when the graph is given ??? ask for the gradient or y-intercept of a graph from an equation, e.g. find the gradient and y-intercept of the graph with equation 5x + 4y = 8. Candidates are expected to give equations of a line in a fully simplified form.