A photograph print measuring 24cm by 15 cm is enclosed in a frame.

A uniform space of width x cm is left in between the edges of the photograph and the frame. If the area of the space is 270cm', find the value of x.

1 answer

new dimension: 24+2x by 15+2x
entire area = (24+2x)(15+2x)

(24+2x)(15+2x) - (24)(15) = 270

solve the resulting quadratic for x
Hint: the simplified quadratic factors nicely, make sure to reject the negative