Question

The area of a rectangle is given by A = x2 + 4x – 5. Find the value of x if the total area of the rectangle is equal to 7 square units.
a) x = 1
b) x = 7
c) x = 5
d) x = 2

Answer 1

Write it as 7 = x^2 + 4x -5. Subtract 7 from both sides to get:
x^2 + 4x - 12. Use the quadratic formula to solve for x. One of the values will be negative, ignore that, x has to be positive. :-)