Question

the length of a photograph is 1 cm less than twice the width. the area is 28 cm squared. find the dimensions of the photograph.

Answer 1

So the formula for the area of this photograph would be the following:

area = length x width
(let's fill in what we know from the question into this formula)

28 =(2w-1) * w
(Now let's use the distribution rule and multiply everything in the brackets by 'w')
28 = 2w^2-w
(Now let's set this equation to zero)
0=2w^2-w-28
(If you noticed, this equation in the form of y=ax^2+bx+c)

Now at this point you could use the quadratic question to solve for 'w'.

What I got for my values were -3.5 and 4
Since -3.5 does not make sense realistically, you would go with 4 cm.

Let's plug this back into the question to see if we're correct:

28 =(2w-1) * w
28= (2[4]-1)*4
28 = (8-1)*4
28 = 7*4
28 = 28

Therefore the width is 4 cm and length is 7 cm