Examples of Math Problems
examples of math problems that I like, solved, etc.
Wednesday, October 16, 2013
how do i do this: 1 /loga(abc) +1 /logb(abc) +1 /logc(abc) ?
use the change of base identity:
1 /loga(abc) +1 /logb(abc) +1 /logc(abc)=
(log(a)+log(b)+log(c))/log(abc)
Sunday, October 13, 2013
solve: 1) 3x+y=17, 2) 4x-y=18
1) 3x+y=17
2) 4x-y=18
adding the two equations yields:
7x=35
thus
x=5
now we can find y...
3*5+y=17
y=2
Factor: 15y^2+8y+1
since 3*5=15 and 3+5=8...
15y^2+8y+1=
15y^2+3y+5y+1=
(15y^2+3y)+(5y+1)=
3y(5y+1)+1(5y+1)=
(3y+1)(5y+1)
James is 4 years older than Kabul. In two years, their ages will total 50. How old is James now?
1) j-k=4
2) j+2+k+2=50
j-k=4
j+k=46
2j=50
j=25
what is the truth value of the statement "2+4=6 and 9 is a prime number
Both statements are not true, so the and of them is not true. Thus the statement is false.
Friday, October 11, 2013
find two consecutive odd integers such that three times the smaller one exceeds two times the larger one by 7
1) n-m=2 <-- consecutive odds differ by 2
2) 3m+7=2n
3(n-2)+7=2n
3n-6+7=2n
n=-1
so m=-3
For what value of x is this inequality |x – 6|< - 8 true? Why?
for no value of x...
|x – 6|< - 8
has no solution because an absolute value of a real valued expression can never (by definition) be negative. Therefore it can never be less than -8
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