2х + 5y = 6x+2y = -3 what is x?

Mathematics

1 answer:

likoan [24]4 years ago

8 0

Answer:

x = -3

In-Depth Steps:

1.) Start with the bottom equation: $x+2y=-3$

2.) Set $x$ alone on one side of the equal sign. Your equation will look like $3+2y=x$ .

3.) Plug $3+2y$ in for $x$ in the first equation. You will get $2(3+2y)+5y=6$ .

4.) Distribute. Your equation now looks like this: $(6+4y)+5y=6$ .

5.) Combine like terms. You will get $6+9y=6$ .

6.) Subtract 6 from both sides. You get $9y=0$ . We can learn that Y=0.

7.) Go back to either equation and put 0 in for y.

8.) In the top equation, it would look like $2x=6$ and the bottom equation would look like $x=-3$ . We basically got our answer of $x = -3$ , but we will plug it into the $2x=6$ equation, and in-fact, we get x = -3.

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30pts BRAINLIEST please help? also if possible id love to learn how to find the answer so i can do this later on by myself. Than

makkiz [27]

Step 1) Enter the (x,y) pairs of values into a table. In the attached image, this is in columns B and C

Step 2) Make a new column of the squared x values. This is column D in that same attached image

Step 3) Make another column of the x*y values. This is the result of multiplying each (x,y) pair together. This is column E.

Step 4) Add up everything in their respective columns. The sums are highlighted in yellow at the bottom. Those sums are important since we'll use them later.

Let
P = sum of the x values = 22
Q = sum of the y values = 56
R = sum of the x^2 values = 75
S = sum of the x*y values = 111

We'll use P,Q,R,S in the formulas below

m = (n*S-P*Q)/(n*R-P^2)
b = (Q - m*P)/n

where m is the slope, b is the y intercept and n is the number of points (in this case, n = 8). The regression line is in the form y = mx+b

So let's compute the slope m first
m = (n*S-P*Q)/(n*R-P^2)
m = (8*111-22*56)/(8*75-22^2)
m = -2.96551724137931
which rounds to m = -3

Then use this m value to find b
b = (Q - m*P)/n
b = (56 - (-2.96551724137931)*22)/8
b = 15.1551724137931
which rounds to b = 15

So y = mx+b turns into y = -3x+15

----------------------------------------

Final Answer: Choice A) y = -3x+15
This regression line is approximate to the nearest whole number

Side Notes:
1) If your teacher doesn't want you using that formula I mentioned above, then you can try looking in your book for similar versions of the formula

2) If your teacher requires you only use two points, then I suggest you find the equation of the line through (1,12) and (4.5,0) to get roughly the same answer if you rounded to the nearest whole number

3) Using a calculator, such as a TI83, will help speed up the process immensely. The LINREG function will automatically find the linear regression equation after you type in the x,y values into the table. Let me know if you need me to go over this in greater detail.