A ruler costs x pence. a pen costs 10 pence more than a ruler.
write an expression, in terms of x, for the cost of a pen.

a 90 degree rotation across the the origin followed by a reflection across the x-axis.

step-by-step explanation:

set the two equations for y equal to each other. solve for x. this will be the x-coordinate for the point of intersection. use this x-coordinate and plug it into either of the original equations for the lines and solve for y.