2x + 4y = 14
4x + y = 20......multiply by -4
----------------
2x + 4y = 14
-16x - 4y = -80 (result of multiplying by -4)
---------------add
-14x = -66....as u can see, ur y's cancel out
so ur answer is : 1st answer choice <==
** and just so u know, u could have multiplied the 1st equation by -2, and it would have cancelled out ur x's
Answer:
The correct answer is x= 4/5 because you cannot take the root of a negative number
Answer:
4c^2+7c-5=0
4c^2+7c=5
4c^2+7c=5
4c^2+7c-5=0\quad :\quad c=\frac{-7+\sqrt{129}}{8},\:c=\frac{-7-\sqrt{129}}{8}\quad \left(\mathrm{Decimal}:\quad c=0.54472\dots ,\:c=-2.29472\dots \right)
Hope This Helps!!!
Supposing, for the sake of illustration, that the mean is 31.2 and the std. dev. is 1.9.
This probability can be calculated by finding z-scores and their corresponding areas under the std. normal curve.
34 in - 31.2 in
The area under this curve to the left of z = -------------------- = 1.47 (for 34 in)
1.9
32 in - 31.2 in
and that to the left of 32 in is z = ---------------------- = 0.421
1.9
Know how to use a table of z-scores to find these two areas? If not, let me know and I'll go over that with you.
My TI-83 calculator provided the following result:
normalcdf(32, 34, 31.2, 1.9) = 0.267 (answer to this sample problem)
