Posted by Shaw on .
If the length of a rectangle is (2x1)cm and its width is (x+3)cm.
How do i write an expression in the form ax^2+bx+c for the area of the rectangle?
Given that the area of the rectangle is 294cm^2, determine the value of x and state the dimensions of the rectangle in cms?? want the working so i can do questions like these in the future.

Math 
Reiny,
Area = length x width, so
Area = (2x1)(x+3)
expand this and you got the first part
(did you get 2x^2 + 5x  3 ?)
now set this equal to 294
2x^2 + 5x  3 = 294
2x^2 + 5x  297 = 0
rather than waste time trying to factor this with these numbers, I would use the quadratic formula 
Math 
Anonymous,
594