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miss Akunina [59]
2 years ago
15

Solve the system using elimination

Mathematics
1 answer:
gayaneshka [121]2 years ago
6 0

Step-by-step explanation:

-4x + 9y = -22

-9x -9y = 126

-13x = 104

x = -8

8 +`y = 14

y = 6

(-8,6)

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Solve 3/4x = 7 28/ 3​
Olegator [25]

3/4x=728/3

x=728/3×4/3

x=32.556

HOPE IT HELPS YOU OUT PLEASE MARK IT AS BRAINLIEST AND FOLLOW ME PROMISE YOU TO FOLLOW BACK ON BRAINLY.IN

BUT I'M NOT SURE IF IT IS CORRECT

6 0
3 years ago
A man age is three times his sons age. ten years ago was five times his sons age. find their current age.
kow [346]

Answer:

The son is 20

The man is 60

Step-by-step explanation:

We can set up this equation with what we know. Let <em>m</em> stand for the Man's current age, and let <em>s</em> stand for his son's current age.

We know the Man's current age is three times that of his son, so this equation can be written as: <em>m = 3s</em>

Ten years ago means the man's current age <em>minus</em> 10 years. So it is <em>m-10</em>. So ten years ago he was 5 times his son's age 10 years ago, <em>5(s-10)</em>

This can be written as: <em>m-10=5(s-10)</em>

Solve with either substitution or elimination, the choice is yours, it doesn't really matter which method you use. I'll be using substitution.

<em>m-10=5(s-10)</em>

<em>3s-10= 5s-50</em>

<em>40=2s</em>

<em>20 = s</em>

The son is <em>20</em> years old.

We know the man is currently 3 times his son's age, because <em>m=3s</em>, so just solve for m since you now know the value of <em>s.</em>

<em>m=3s</em>

<em>m=3(20)</em>

<em>m=60</em>

The man is <em>60</em> years old

4 0
3 years ago
A 7m wide path is to be constructed all around and outside a circular park of diameter
Assoli18 [71]

Answer:

392m^2

Step-by-step explanation:

as the length = diameter of the circular park

then

Area = length * width = 56 * 7 = 392m^2

8 0
2 years ago
Read 2 more answers
Please help!
ch4aika [34]

Answer:

C

Step-by-step explanation:

5 0
3 years ago
Read 2 more answers
QUICK EASY 25 POINTS!!
MAVERICK [17]

Answer:

1. leave the radical symbol and don't try to convert it to a decimal form

2. The approximated value differs from the exact solution and doesn't give a true equation.

3. Depending on the case, if she needs a mathematical answer, the exact value should be used, but for more practical applications, the rounded decimal form would be more usable.

Step-by-step explanation:

The step by step solution to the equation:

4x^3=756\\x^3=\frac{756}{4} =189\\x=\sqrt[3]{189} \\x=\sqrt[3]{3^3*7} \\x=3*\sqrt[3]{7}

1.- Exact solution means that if in the final step when solving for x the value of  x^3 is not a perfect cube, one needs to leave it indicated as a radical expression (with the radical symbol).

in our case, the cubic root of 189 is not a perfect cube. The factor form of 189 is: 3^3*7, so there is a perfect cube factor (3^3), but the other factor (7) is a prime number. Therefore 3 can get out of the root, while 7 stays inside.

2.- The equation was solved above, in exact form. Now to solve it giving a decimal approximation, we use a calculator to find the cubic root of 7, which is an irrational number with infinite number of decimals, the first of which we type here: \sqrt[3]{7} = 1.91293118...

Therefore, the decimal approximation to the solving for x would be:

x=3*\sqrt[3]{7}=3*1,91293118...=5.73879...=5.74

Where we rounded to two decimals as requested.

When we replace the exact answer in the original expression, we get a perfect equality:

4*x^3=756\\4* (3\sqrt[3]{7} )^3=756\\4*3^3*(\sqrt[3]{7} )^3=756\\4*27*7=756\\\\756=756

While if we use the approximate answer, we get:

4*x^3=756\\\\4*(5.74)^3=756\\\\4*189.119224=756\\756.476896=756

which is NOT a true equality.

3.- I would stick with the idea of showing the exact answer as answer to the mathematical equation. but for a practical case (for example she needs to by some material as a result of her equation solving, it would be more practical to take the numerical approximation to the store, instead of a cubic root of a number.

7 0
3 years ago
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