Answer:
Prove if certain shapes fit the criteria, and if they are congruent or not
Step-by-step explanation:
Geometric proofs prove if certain shapes are congruent, whether they are not. They can also prove if sides are equal when values are not given, if a certain shape fits certain criteria, and can prove the length of certain lines when the values are not given.
<span>Length = 1200, width = 600
First, let's create an equation for the area based upon the length. Since we have a total of 2400 feet of fence and only need to fence three sides of the region, we can define the width based upon the length as:
W = (2400 - L)/2
And area is:
A = LW
Substitute the equation for width, giving:
A = LW
A = L(2400 - L)/2
And expand:
A = (2400L - L^2)/2
A = 1200L - (1/2)L^2
Now the easiest way of solving for the maximum area is to calculate the first derivative of the expression above, and solve for where it's value is 0. But since this is supposedly a high school problem, and the expression we have is a simple quadratic equation, we can solve it without using any calculus. Let's first use the quadratic formula with A=-1/2, B=1200, and C=0 and get the 2 roots which are 0 and 2400. Then we'll pick a point midway between those two which is (0 + 2400)/2 = 1200. And that should be your answer. But let's verify that by using the value (1200+e) and expand the equation to see what happens:
A = 1200L - (1/2)L^2
A = 1200(1200+e) - (1/2)(1200+e)^2
A = 1440000+1200e - (1/2)(1440000 + 2400e + e^2)
A = 1440000+1200e - (720000 + 1200e + (1/2)e^2)
A = 1440000+1200e - 720000 - 1200e - (1/2)e^2
A = 720000 - (1/2)e^2
And notice that the only e terms is -(1/2)e^2. ANY non-zero value of e will cause this term to be non-zero and negative meaning that the total area will be reduced. Therefore the value of 1200 for the length is the best possible length that will get the maximum possible area.</span>
Answer:
(-4,2) belongs in this direct variation.
Step-by-step explanation:
Let the direct variation relationship is expressed by the equation y = mx ........ (1), where x and y are in direct variation and k is the variation constant.
Now, the point (4,-2) is included in the direct variation relationship, then from equation (1) we get, -2 = 4m
⇒ 
Therefore, the equation (1) becomes 
⇒ x + 2y = 0 ......... (2)
Now, from the given four options only the point (-4,2) satisfies the relation (2).
Hence, (-4,2) belongs in this direct variation. (Answer)
Answer:
x = -1, y = -4
Step-by-step explanation:
Let's solve our system of equations by substitution.
y = 5x + 9y = −x + 3
Step: Solve = 5x + 9 for y:
y = 5x + 9
Step: Substitute 5x + 9 for y in y = −x + 3:
y = −x + 3
5x + 9 = −x + 3
5x + 9 + x = −x + 3 + x (Add x to both sides)
6x + 9 = 3
6x + 9 + −9 = 3 + −9 (Add -9 to both sides)
6x = −6
6x/ 6 = −6/6(Divide both sides by 6)
x = −1
Step: Substitute −1 for x in y = 5x + 9:
y = 5x + 9
y = (5)(−1) + 9
y = 4(Simplify both sides of the equation)
So our answers are y = -4 and x = -1.
