Exponents can make the problem smaller and look less confusing. If you see a problem with 5*5*5*5*5*5*5*5 then you're going to eventually loose count and will have to keep repeating. But if you put 5 to the 8th power then you know right away just to multiply 5, (8) times,
The denominator would still be the same you placed the marble back into the bag
Part A. What is the slope of a line that is perpendicular to a line whose equation is −2y=3x+7?
Rewrite the equation −2y=3x+7 in the form
Here the slope of the given line is
If
is the slope of perpendicular line, then
![m_1\cdot m_2=-1,\\ \\m_2=-\dfrac{1}{m_1}=\dfrac{2}{3}.](https://tex.z-dn.net/?f=m_1%5Ccdot%20m_2%3D-1%2C%5C%5C%20%5C%5Cm_2%3D-%5Cdfrac%7B1%7D%7Bm_1%7D%3D%5Cdfrac%7B2%7D%7B3%7D.)
Answer 1: ![\dfrac{2}{3}](https://tex.z-dn.net/?f=%5Cdfrac%7B2%7D%7B3%7D)
Part B. The slope of the line y=−2x+3 is -2. Since
then lines from part A are not parallel to line a.
Since
both lines are not perpendicular to line a.
Answer 2: Neither parallel nor perpendicular to line a
Part C. The line parallel to the line 2x+5y=10 has the equation 2x+5y=b. This line passes through the point (5,-4), then
2·5+5·(-4)=b,
10-20=b,
b=-10.
Answer 3: 2x+5y=-10.
Part D. The slope of the line
is
Then the slope of perpendicular line is -4 and the equation of the perpendicular line is y=-4x+b. This line passes through the point (2,7), then
7=-4·2+b,
b=7+8,
b=15.
Answer 4: y=-4x+15.
Part E. Consider vectors
These vectors are collinear, then
![\dfrac{-c}{-b}=\dfrac{d}{a},\quad \text{or}\quad -\dfrac{a}{b}=-\dfrac{d}{c}.](https://tex.z-dn.net/?f=%5Cdfrac%7B-c%7D%7B-b%7D%3D%5Cdfrac%7Bd%7D%7Ba%7D%2C%5Cquad%20%5Ctext%7Bor%7D%5Cquad%20-%5Cdfrac%7Ba%7D%7Bb%7D%3D-%5Cdfrac%7Bd%7D%7Bc%7D.)
Answer 5: ![-\dfrac{a}{b}=-\dfrac{d}{c}.](https://tex.z-dn.net/?f=-%5Cdfrac%7Ba%7D%7Bb%7D%3D-%5Cdfrac%7Bd%7D%7Bc%7D.)
Given:
The measure of three sides of a triangle are 8, 7 and 14.
To find:
The measure of the angle opposite the side of length 8.
Solution:
According to the Law of Cosine:
![\cos A=\dfrac{b^2+c^2-a^2}{2bc}](https://tex.z-dn.net/?f=%5Ccos%20A%3D%5Cdfrac%7Bb%5E2%2Bc%5E2-a%5E2%7D%7B2bc%7D)
Let a=8, b=7 and c=14, then by using Law of Cosine, we get
![\cos A=\dfrac{7^2+14^2-8^2}{2(7)(14)}](https://tex.z-dn.net/?f=%5Ccos%20A%3D%5Cdfrac%7B7%5E2%2B14%5E2-8%5E2%7D%7B2%287%29%2814%29%7D)
![\cos A=\dfrac{49+196-64}{196}](https://tex.z-dn.net/?f=%5Ccos%20A%3D%5Cdfrac%7B49%2B196-64%7D%7B196%7D)
![\cos A=\dfrac{181}{196}](https://tex.z-dn.net/?f=%5Ccos%20A%3D%5Cdfrac%7B181%7D%7B196%7D)
Taking cos inverse on both sides.
![A=\cos^{-1}\dfrac{181}{196}](https://tex.z-dn.net/?f=A%3D%5Ccos%5E%7B-1%7D%5Cdfrac%7B181%7D%7B196%7D)
![A=22.561328](https://tex.z-dn.net/?f=A%3D22.561328)
![A\approx 22.6](https://tex.z-dn.net/?f=A%5Capprox%2022.6)
Therefore, the measure of the angle opposite the side of length 8 is 22.6 degrees.