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3 years ago

4x + 2y = -12 3x + y = -10 please help system by substitution.

Mathematics

1 answer:

padilas [110]3 years ago

3 0

Answer:

(-4, 2)

Step-by-step explanation:

4x+2y=-12

3x+y=-10

Start by dividing the first equation by 2 to simplify it...

2x+y=-6

Then, subtract -2x from both sides to isolate y...

y=-2x-6

Substitute -2x-6 for y in the second equation...

3x-2x-6=-10

Combine like terms...

x-6=-10

Add 6 to both sides

x-6+6=-10+6

x=-4

Plug -4 in for x to solve for y:

3(-4)+y=-10

-12+y=-10

Add 12 to both sides

-12+12+y=-10+12

y=2

(x,y)=(-4,2)

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4 years ago

Melissa buys 2 1/2 pounds of salmon and 1 1/4 pounds of swordfish. She pays a total of $31.25, and the swordfish cost $.20 per p

julsineya [31]

Answer:

The combined cost of 1 pound of salmon and 1 pound of swordfish is $16.66

Step-by-step explanation:

Let us assume the cost of 1 pound salmon = $ m

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Now, the Amount of salmon purchased = 2 1/2 pounds

$2\frac{1}{2} = 2 + \frac{1}{2} = 2 + 0.5 = 2.5$

So, the amount of salmon purchased = 2.5 pounds

Cost of buying 2.5 pounds = 2.5 x ( 1 pound cost)

= 2.5 ( m) = $ 2.5 m ...... (1)

Also, the Amount of swordfish purchased = 1 1/4 pounds

$1\frac{1}{4} = 1 + \frac{1}{4} = 1 + 0.25 = 1.25$

So, the amount of swordfish purchased = 1.25 pounds

Cost of buying 1.25 pounds = 1.25 x ( 1 pound cost of swordfish)

= 1.25 ( m - 0.20) = $ 1.25 m - 0.25 .... (2)

Now, the combined cost paid = $ 31.25

⇒Cost of buying (2.5 pounds salmon + 1.25 pounds swordfish) = $ 31.25

or, 2.5 m + 1.25 m - 0.25 = 31.35 (from (1) and (2))

or, 3.75 m = 31.60

or, m = 31.60/3.75 = 8.43

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4 years ago

Evaluate p(-2)=x^3-4x-5

Pani-rosa [81]

Step-by-step explanation:

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3 years ago

Read 2 more answers

when you solve a problem by working backward, what does your answer represent? how can you check your answer?

Rus_ich [418]

Lets say you have an addition problem

3 + 7 = ?

To figure that you can just add in your head since its easy.

3 + 7 = 10

You can work backwords to check to see if your awnser is right.

When you work backwards you do the opposite of what you are doing, so if your adding the opposite would be subtracting, and if your multiplying than the opposite would be dividing.

So you could work it out like this:

(Regular⬇️)
3 + 7 = 10
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10 - 7 = 3

And if you get the same numbers that were in the original awnser than you are correct! Hope this helps!!!!

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3 years ago

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iogann1982 [59]

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3 years ago