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
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.
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