Answer:
C. 8x - 3y = 5
Step-by-step explanation:
7 - 3(x - y) = 5x + 2
Standard form: Ax + By = C
7 -3x + 3y = 5x + 2
7 -8x + 3y = 2
-8x + 3y = -5
Divide by -1 to each number
8x - 3y = 5
Answer:
Options A-C-F
Step-by-step explanation:
we know that
<em>The circumference of a circle is equal to</em>
or 
where
D is the diameter and r is the radius
therefore
or 
The number pi is the ratio circumference - diameter or is the ratio circumference - 2 times radius
<em>The area of the circle is equal to</em>
therefore
The number pi is the ratio Area - radius squared
Answer:
The roots of the equation 2m²+3=m are non-real roots.
Step-by-step explanation:
Given equation:
2m²+3=m
2m²-m+3=0
Here, from the equation we can obtain the following values:
a = 2, b = -1, c = 3
Discriminant of an equation is given as:
D = b²-4ac
= (-1)²-4(2)(3)
= 1 - 21
= -20
Discriminant can tell what kinds of roots the equation have.
In our case, the discriminant is less than 0.
When D < 0, the roots of the equation are complex conjugates.(non-real)
Answer: Option #4: the 0.2 could be changed to 2.
Explanation:
The table is designed to make the concept of percentages more understandable. The table first allocates the total amount of 70 in terms of its "fifths," or 20% parts. Then it expresses these parts in the last row of the table, showing that 20% of 70 is 14 and all the five parts sum up to 70 again.
Now, Mikel is supposed to express 40% of the amount. So she writes (incorrectly): 0.2 * 14. This statement needs to be changed to 2 * 14 (two times 14 = 28), to correspond to 2 times 20%, or 40% of 70.
This is reflected in the last (fourth) option "The 0.2 in the expression could be changed to 2."
Option #3 is incorrect because changing 14 to 70, will result in an incorrect number (2.8).
Options 1 and 2 are similarly incorrect (as can be easily verified)
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
