Hallie can use the equation p = 4l + 4w + 4h to determine the sum of the lengths of the edges of a rectangular prism. She begins to solve the equation for h but runs out of time. Her partial work is shown below:
p = 4l + 4w + 4h
2. StartFraction p Over 4 EndFraction equals StartFraction 4 l plus 4 w plus 4 h Over 4.
3. StartFraction p Over 4 EndFraction equals l plus w plus h. = l + w + h
h = 4. h equals StartFraction p Over 4 EndFraction minus blank. –
Which expression should follow the subtraction in Hallie’s equation?
(l + w)
(l – w)
left-parenthesis StartFraction l plus w Over 4 right-parenthesis.
left-parenthesis StartFraction l plus w Over 4 EndFraction right-parenthesis.
The expression (w + h) + p/4 should follow the subtraction if Hallie's equation is
p = 4l + 4w + 4h
p/4 = l + w + h
h = -
Hallie can use the following equation to solve the problem
p = 4l + 4w + 4h
She can proceed to make h the subject of the formula.
p = 4l + 4w + 4h
When we factor out 4 on the right hand side, we get:
p = 4(l + w + h)
We then divide both side by 4, we have
p/4 = l + w + h
Then, subtracting (l + w) from both sides, we get:
p/4 - (l + w) = h.
We can write it as:
h = - (l + w) + p/4
And that is what Hallie wanted to obtain.