Answer:
3.9
Step-by-step explanation:
Pythagorean theorem:
a^2 + b^2 = c^2
a^2 + 1^2 = 4^2
a^2 + 1 = 16
a^2 = 15
a = sqrt(15)
a = 3.9
Answer a = 3.9 yards
3x=4y
x+y=21
x = 21-y
3(21-y)=4y
63-3y=4y
63=7y
y=9
x+y=21
x+9=21
x=12
answer is (12, 9)
1: Assuming this line is linear, the first thing to do is find the slope.
The slope formula is

, so in this case, it is

, which comes to

. Then, use your slope and one of the points given to write the point-slope formula of the linear equation, and then written in standard form:
y=

x-

.
2. Use the same process as in question 1 to find:
y=-7x+11
Answer: x = 30°
Concept:
Here, we need to know the idea of an isosceles triangle and the vertical angle theorem.
An <u>isosceles triangle</u> is a triangle that has any two of its sides equal to each other. Also, the angles opposite these equal sides are equal, which is basically the base angles.
The <u>vertical angle theorem</u> states that two vertical angles formed when two lines intersect each other are always equal to each other.
Solve:
<u>Find the other base angle of the isosceles triangle.</u>
Since there are two equal sides, we know that this is an isosceles triangle.
Since the definition said that the base angles are equal, the other base angle would also be x.
<u>Find the value of x</u>
According to the vertical angle theorem, two vertical angles formed by intersection are equal.
Just as angle x and 30°, are vertical angles formed by intersection, therefore, 
Hope this helps!! :)
Please let me know if you have any questions
<h3>Answer: Choice B) </h3><h3>-6x - 2y = 12</h3>
===============================================
Explanation:
The x intercept is (-2,0) which is where the graph crosses the x axis.
The y intercept is (0,-6) which is where the graph crosses the y axis.
-----
Find the slope of the line through those two points
m = (y2-y1)/(x2-x1)
m = (-6-0)/(0-(-2))
m = (-6-0)/(0+2)
m = -6/2
m = -3
-----
The y intercept (0,-6) leads to b = -6
Both m = -3 and b = -6 plug into y = mx+b to get
y = mx+b
y = -3x+(-6)
y = -3x-6
-----
Now add 3x to both sides
y = -3x-6
y+3x = -3x-6+3x
3x+y = -6
-----
Lastly, multiply both sides by -2 so that the "-6" on the right hand side turns into "12" (each answer choice has 12 on the right hand side)
3x+y = -6
-2(3x+y) = -2(-6)
-2(3x)-2(y) = 12
-6x-2y = 12
which is what choice B shows.