Answer:
x=-7
Step-by-step explanation:
xe^-x+7e^-x=0
factor out the e^-x
e^-x(x+7)=0
e^-x=0, x+7=0
-x=ln(0), x=0-7=-7,
since ln(0) is undefined,
the only solution is -7.
Answer:
Step-by-step explanation:
3z-4=6z-17
-3z-4=-17 (subtracted the 6z from both sides)
-3z=-13 (added the 4 to both sides)
z=
(divided both sides by -3z)
z=
Answer:
24 tests
Step-by-step explanation:
Since 32 equals one hour and one hour is the total, we can see that 15 minutes equal 1/4, or 25%, 30 minutes equal 2/4, or 50%, and 45 minutes equal 3/4, or 75%. So, we can divide 32 by 4 to find out 1/4, or 25%, which equals 8. You can then multiply 8 by the number of fourths in 75% or 45 minutes, which is 3. 8 x 3 equals 24, so Mrs. Wilbur can grade 24 tests in 45 minutes.
