SOLUTION: the altitude of a triangle is 5 m less than its base. The area of the triangle is 42 meters squared find the base.

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Question 443371: the altitude of a triangle is 5 m less than its base. The area of the triangle is 42 meters squared find the base.
Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
The altitude (AKA height) can be represented as b-5. The base is b.
Recall that the formula for area is A+=+%281%2F2%29b%2Ah
42+=+%281%2F2%29+%2A+b+%2A+%28b-5%29}
84+=+b%5E2+-5b
b%5E2-5b+-84+=+0
Let's factor this:
What adds to -5 and multiplies to -84?
-12 and 7.
So we can factor this as (b-12)(b+7)
So b =-7, b = 12
A negative length doesn't make sense so...
The base is 12.