Answer:
0
Step-by-step explanation:
x2 +4x-21=0. solve for x
Answer:
Step-by-step explanation:
<u>Completing the square</u>
when 
Given equation:
Subtract 40 from both sides:
Divide both sides by 3:
Add the square of half the coefficient of 
to both sides:
Factor the left side and simplify the right side:
Square root both sides:
Add 4 to both sides and simplify the radical:
9514 1404 393
Answer:
9, the sum of the numbers given in the ratio
Step-by-step explanation:
The reduced ratio 2 : 7 means that two parts correspond to one length and 7 parts correspond to the other length. That is, there are a total of 2+7 = 9 parts in the full length of the segment.
It is convenient to think of the line segment as being divided into 9 equal parts.
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<em>Additional comments</em>
It is often helpful to consider the total number of "ratio units" in a given ratio. For example, in this problem, the shorter segment is 2/9 of the whole, and the longer one is 7/9 of the whole.
It can also be useful to consider what a "ratio unit" represents. If the whole segment is 27 inches long, then each of the 9 ratio units will represent 3 inches, for example. This means the division 2:7 is 2(3 in):7(3 in) = 6 in : 21 in.
