Graphs 7
3 marks · NormalTwo graphs are drawn: and .
Explain how you would use these graphs to solve the equations:
a)
b)
Show clear reasoning.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Also accept: Clear explanation involving intersection points and equation rearrangement.
Common mistakes: Not distinguishing between the two forms; not linking intersections with solutions.
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Links solving to intersection points of the two graphs.
B2 · 1 mark · Recognises that is equivalent to the previous equation; shows equivalent rearrangement.
B3 · 1 mark · States clearly that x-values of intersection are the solutions to both equations.
Worked solution
a) Where the graphs of and intersect, the y-values are the same, so . The x-values at these points are the solutions.
b) Rearranging gives , so both equations have the same solutions. Thus, the intersection points also solve part (b).