Answer:
![\boxed{-20i^2 -13ij+21j^2}](https://tex.z-dn.net/?f=%5Cboxed%7B-20i%5E2%20-13ij%2B21j%5E2%7D)
Step-by-step explanation:
![\sf Plug \ in \ the \ values.](https://tex.z-dn.net/?f=%5Csf%20Plug%20%5C%20in%20%5C%20the%20%5C%20values.)
![(5i+7j) \cdot (-4i+3j)](https://tex.z-dn.net/?f=%285i%2B7j%29%20%5Ccdot%20%28-4i%2B3j%29)
![\sf Expand \ brackets.](https://tex.z-dn.net/?f=%5Csf%20Expand%20%5C%20brackets.)
![5i(-4i+3j)+7j(-4i+3j)](https://tex.z-dn.net/?f=5i%28-4i%2B3j%29%2B7j%28-4i%2B3j%29)
![-20i^2 +15ij+-28ij +21j^2](https://tex.z-dn.net/?f=-20i%5E2%20%2B15ij%2B-28ij%20%2B21j%5E2)
![\sf Combine \ like \ terms.](https://tex.z-dn.net/?f=%5Csf%20Combine%20%5C%20like%20%5C%20terms.)
![-20i^2 -13ij+21j^2](https://tex.z-dn.net/?f=-20i%5E2%20-13ij%2B21j%5E2)
They are already rounded but 20% and 30% should be correct.
Point estimate is the method of looking for an approximate value of some parameter - example: the mean (average) and it could be also the sample standard deviation of a population from random samples of the population.
To get the point estimate: 20 (people wearing hearing aids) / 304 (total random sample) = 0.0657894 or 0.066
:
Step-by-step explanation:
2x^2-3x-5=y
(2x-5)(x+1)=y
(2x-5)(x+1)=0
2x-5=0
2x=5
x=2.5
x+1=0
x=-1
you have an even degree (2) and a positive coefficient (2)
therefore as x---> -∞, f(x)----> +∞
also, as x----> +∞, f(x)----> +∞
also notice that this is a parabola that opens upwards so both "ends" approach positive infinity
plot the x-intercepts, find the vertex using h=-b/2a and substituting this value into the equation to find k and make a table of values to graph the parabola unless you only want a rough sketch of the graph-you know the x-intercepts and you found the vertex using h=-b/2a