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maks197457 [2]
4 years ago
12

Solving systems by substitutions

Mathematics
1 answer:
svp [43]4 years ago
8 0
Let's take two different equations.

4x+2y=8
7x+3y=-10
(I just came up with these on the spot, so the answers might be strange but i should be able to explain nevertheless)
First, let's solve the first equation for "y".
4x+2y=8
-4x      -4x
2y=8-4x
/2
y=4-2x
Now that we have "y", let's plug it into the second equation.
7x+3(4-2x)=-10
7x+12-6x=-10
x+12=-10
-12    -12
x=-22
Alright, now we have "x" definitively, let's plug it in to find "y".
4(-22)+2y=8
-88+2y=8
+88       +88
2y=96
/2
y=48
So from this example you can see. You solve one variable in terms of another (solve y as being 4-2x), plug it into the second equation to find one variable's value, then plug that variable's value back in again later to get the first variable's value.
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You can jog around the block twice and the park once in 10 min. You can jog around the block twice and the park 3 times in 22 mi
stich3 [128]
B = block     p = park

2b + p = 10 min                2 runs around the block takes 10 minutes
2b + 3p = 22 min        2 runs around the block plus 3 runs around the park                                                       takes 22 minutes

To solve, I will use substitution. First, I will divide the first equation by 2 to get b by itself and subtract p from both sides to get b by itself. Then, substitute 5 - 1/2p in for b in the second equation because they have equal values. Then, subtract 10 from both sides to eliminate it. Divide by 2 to both sides to get 'p' by itself.

2b + p = 10 min ---------→b + 1/2p = 5 ----------→ b = 5 - 1/2p

2(5 - 1/2p) + 3p = 22 ---------→ 10 -p + 3p = 22 --------→ 10 + 2p = 22

10 + 3p = 22 ----------→ 2p = 12

2p = 12 -------------→ p = 6

It takes 6 minutes to jog around the park

Hope this helps!
6 0
3 years ago
Can someone help please?!?! Quickly
Yanka [14]

Part 1) Finding x

Note the double tickmarks for segments XY and YZ. This indicates the segments are the same length, which leads to point Y being the midpoint of segment XZ.

Therefore, XZ is twice as long as XY

XZ = 2*( XY )

XZ = 2*( 2x-1 )

XZ = 4x - 2

We also know that XZ = 2(3x-4) = 6x-8. Let's equate 4x-2 and 6x-8 and solve for x

6x-8 = 4x-2

6x-4x = -2+8

2x = 6

x = 6/3

x = 3

<h3>Answer is 3</h3>

=====================================

Part 2) Finding the length of YZ

The resut of part 1 (x = 3) is plugged into the equation for XY to get

XY = 2*x-1

XY = 2*3-1

XY = 6-1

XY = 5

Segment XY is 5 units long. So is segment YZ as these two segments are the same length (aka congruent).

<h3>Answer: 5</h3>

=====================================

Part 3) Finding the length of segment XZ

The answer from the previous part was 5. This doules to 5*2 = 10

-----

A longer way to get the same answer is to plug x = 3 into the XZ equation and we get...

XZ = 2*(3x-4)

XZ = 2*(3*3-4)

XZ = 2*(9-4)

XZ = 2*5

XZ = 10

and we get the same answer

<h3>Answer: 10</h3>
5 0
4 years ago
A student missed 3 questions on a 30 question test. what percent did she get correct?
Lyrx [107]

Answer:

90%

Explanation: 27/30 ÷ 3 = 9/10

9/10 ⇒ 9 x 10 = 90%

4 0
3 years ago
Please help. If U = 5 feet, V = 8 feet, W = 3 feet, X = 6 feet, Y = 13 feet, and Z = 4 feet, what is the area of the object?
Natalija [7]

Answer:3

Step-by-step explanation:

Because it’s the right equation

4 0
4 years ago
Polynomials in factored form 6ab³c² + 21ab²c²
Free_Kalibri [48]

Answer:

6ab {}^{2} c {}^{2}  + 21ab^{2}c {}^{2} \\ =  3ab {}^{2} c {}^{2}  \times (2b + 7)

hope this helps!ت︎

4 0
3 years ago
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