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lorasvet [3.4K]
3 years ago
8

Please Help Me On These Math Questions!!!!! Solve Each System By Elimination

Mathematics
2 answers:
nikdorinn [45]3 years ago
8 0
The complete answers are attached here.

nekit [7.7K]3 years ago
5 0
11) -x + y = -1 ; 2x - y = 0
y = -1 + x ; 2x - (-1+x) = 0 ⇒ 2x + 1 - x = 0 ⇒x = -1 
y = -1 + (-1) ⇒ y = -2

12) -2x + y = -20 ; 2x + y = 48
y = -20 + 2x ; 2x + (-20 + 2x) = 48 ⇒ 2x -20 + 2x = 48 ⇒ 4x = 48 + 20
                      4x = 68 ⇒ x = 68/4 ⇒ x = 17
y = -20 + 2(17) ⇒ y = -20 + 34 ⇒ y = 14

13) 3x -y = -2 ; -2x + y = 3
y = 3 + 2x ; 3x - (3 + 2x) = -2 ⇒ 3x - 3 - 2x = -2 ⇒ x = -2 + 3 ⇒ x = 1
y = 3 + 2(1) ⇒ y = 3 + 2 ⇒ y = 5

14) x - y = 4 ; x - 2y = 10
x = 4 + y ; (4 + y) - 2y = 10 ⇒ 4 + y - 2y = 10 ⇒ 4 - y = 10 
                  ⇒ -y = 10 - 4 ⇒ -y = 6 ⇒  y = -6
x = 4 + (-6) ⇒ x = 4 - 6 ⇒ x = -2

15) x + 2y = 5 ; 3x + 2y = 17
x = 5 - 2y ; 3(5-2y) + 2y = 17 ⇒ 15 - 6y + 2y = 17 ⇒ -4y = 17 - 15
               ⇒ -4y = 2 ⇒ y = -2/4 ⇒ y = -1/2
x = 5 - 2(-1/2) ⇒ x = 5 + 2/2 ⇒ x = 5 + 1 ⇒ x = 6 
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Answer:

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Step-by-step explanation:

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We are given two points.

(1, 130) and (2, 240)

Here the first coordinate represents the x (time) and the second coordinate represents h(x), which is height.

Now plug these two coordinates and find the two equations.

(1, 130), the equation is

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Therefore, we get

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Now let's form the second equation using the coordinate (2, 240)

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Now let's solve the equations (1) and (2) and find the value of "a" and "b"

a + b = 130 can be written as a = 130 - b

Here we can use the substitution method.

Now plug in a = 130 - b in the second equation, we get

240 = 4(130 - b) + 2b

240 = 520 - 4b + 2b

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Now plug in b = 140 in a = 130 -b and find the value of a

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Now we got a = -10 and b = 140.

We plug in a = -10 and b = 140 in the general form, we gety

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h(x) =

Now plug in x = 11 seconds and find the height.

h(11) = -10(11)^2 + 140 (11)

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= - 1210 + 1540

h(11) = 330 feet,

Therefore, the height of the missile in the air after 11 seconds is 330 feet

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