The shorter piece is 3 feet
The longer piece is 9 feet
Answer:
The prime factors of 15 are: 1,3,5,15
The prime factors of 21 are: 1,3,7,21
The prime factors of 38 are: 1,3,13,39
The prime factor of 42 is : 1,2,3,6,7,14,21,42
1) For a quadratic equation, we'll have two answers typically. We're looking for two numbers that when multiplied give -64, and when added give -12. This is a bit of trial and error, but you go about it by systematically factoring -64 in all possible combinations: 64=-2*32=2*-32=-4*16=4*-16=-8*8. Of these, I can 'see' that I can make -12 with 4 and -16. So the factorization of the equation becomes:
(x-16)(x+4)=0, so x=16 or x=-4.
Answers B and D are correct.
For (2), same trick applies. Rewrite as x²-8x-48=0. Factor as (x+4)(x-12)=0 because 4*-12=-48 and 4-12=-8. The other solution is x=12.
