These problems are called systems of equations. Basically you have two linear equations and you need to find the values for x and y. In other words, all these equation are lines and our answer will be the exact point that the pair of lines intersect. For example, if we get x=1 and y=2 the lines will intersect at point (1,2). Now that you have some background knowledge here comes the tricks and tactics kid.
We know that we can solve one variable equation easily. For example...
x+1=2
x=1 obviously
Cause we have two variables x and y it is not possible to find a solution. For example, in the equation x+y=10, x=1 when y=9 and x=2 when y=8. There is not correct answer.
So what can we do? We have to make a two variable equation into a one variable equation.
There are two ways to do this: substitution and elimination. I will create a sample problem and then solve it using both methods.
x+y=2
2y-y=1
3)
-3x-5y=-7 -----> -12x-20y=-28
-4x-3y=-2 ------> -12x-9y=-6
-12x-20y=-28
-(-12x-9y=-6)
---------------------
-11y=-22
y=2
-3x-5(2)=-7
-3x=3
x=-1
4) 8x+4y=12 ---> 24x+12y=36
7x+3y=10 ---> 28x+12y=40
28x+12y=40
-(24x+12y=36)
---------------------
4x=4
x=1
8(1)+4y=12
4y=4
y=1
5) 4x+3y=-7
-2x-5y=7 ----> -4x-10y=14
4x+3y=-7
+(-4x-10y=14)
-------------------
-7y=7
y=-1
4x+3(-1)=-7
4x=-4
x=-1
6) 8x-3y=-9 ---> 32x-12y=-36
5x+4y=12 ---> 15x+12y=36
32x-12y=-36
+(15x+12y=36)
--------------------
47x=0
x=0
8(0)-3y=-9
-3y=-9
y=3
7)-3x+5y=-2
2x-2y=1 ---> x-y=1/2 ----> x=y+1/2
-3(y+1/2)+5y=-2
-3y-1.5+5y=-2
2y=-0.5
y=0.25
2x-2(0.25)=1
2x=1.5
x=0.75
Answer: 177.5
Step-by-step explanation:so to find to area u need to multiply 16 times 16,which gives u a area of 256. Now to find to Area of circle u need to do 5*5 becuse 5 is the radius,and that is 25. 25*3.14=78.5. So we need to subtract 256-78.5=177.5.
Answer: this is the steps to working the problem and the answer is 54: 3% means 3 out of each 100. if you have 100 items, 3% is just 3. You need more than 100 times as many (you want 354), so x must be more than 100 * 100, right? 3% of 10.62 is less than 1, and the problem says there are 354 :-)
Step-by-step explanation:
Hello!
The formula for finding area of a circle is: π · r²
Diameter is 2x the radius. To find the radius when the diameter is given, divide the diameter by 2.
The diameter is 13. 13 ÷ 2 = 6.5
r = 6.5
6.5² = 6.5 × 6.5 = 42.25
π = 3.14
Multiply 3.14 by 42.25 to get the area
3.14 × 42.25 = 132.665
<em>The area of the circle is 132.665 sq. units, which is the last option.</em>
The formula for a circle's area is 
. We are given an area of 38.465 square inches for a quarter of it.
Multiply this value by 4 to compensate for the quarter circle.
Divide both sides by pi (Note: I'm using the conventional value of 3.14)
Take the positive square root of both sides
The radius is 7 inches. Let me know if you have any questions, thanks!
