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ad-work [718]
2 years ago
13

How do you solve linear equations with substitutions?

Mathematics
1 answer:
Nostrana [21]2 years ago
5 0

Answer:

The method of solving "by substitution" works by solving one of the equations (you choose which one) for one of the variables (you choose which one), and then plugging this back into the other equation, "substituting" for the chosen variable and solving for the other. Then you back-solve for the first variable.

Step-by-step explanation:

Solve the following system by substitution.

2x – 3y = –2

4x +   y = 24

The idea here is to solve one of the equations for one of the variables, and plug this into the other equation. It does not matter which equation or which variable you pick. There is no right or wrong choice; the answer will be the same, regardless. But — some choices may be better than others.

For instance, in this case, can you see that it would probably be simplest to solve the second equation for "y =", since there is already a y floating around loose in the middle there? I could solve the first equation for either variable, but I'd get fractions, and solving the second equation for x would also give me fractions. It wouldn't be "wrong" to make a different choice, but it would probably be more difficult. Being lazy, I'll solve the second equation for y:

4x + y = 24

y = –4x + 24

Now I'll plug this in ("substitute it") for "y" in the first equation, and solve for x:

2x – 3(–4x + 24) = –2

2x + 12x – 72 = –2

14x = 70

x = 5

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5 + 7) + 3 = 5 + (7 + 3)
Liula [17]

Answer:

Step-by-step explanation:

Associative property

3 0
3 years ago
What are the coordinates of point B in the diagram?
shusha [124]
Might be A, I don’t know.
6 0
3 years ago
Después de 15 meses de haber prestado un capital al 5% de rédito, tengo que pagar de interés Q468.75. ¿Qué capital se ha prestad
Aleonysh [2.5K]

The capital borrowed, or the principal when the interest was Q468.75 is <u>Q7500</u>.

The principal P, amount borrowed, at a certain rate of interest R%, for  a time of T years, giving an interest of I, can be calculated using the formula:

P = (I * 100)/(R * T).

In the question, we are asked to find the capital borrowed, that is, the principal, when the user pays Q468.75 after 15 months at 5% of income.

Thus, Interest (I) = Q468.75, rate of interest (R) = 5%, and time (T) = 15 months = 15/12 years = 1.25 years.

Thus, the principal P, can be calculated by substituting the values in the formula: P = (I * 100)/(R * T).

P = (468.75*100)/(5*1.25),

or, P = 46875/6.25,

or, P = 7500.

Thus, the capital borrowed, or the principal when the interest was Q468.75 is <u>Q7500</u>.

The provided question is in Spanish. The question in English is:

"After 15 months of having borrowed capital at 5% of income, I have to pay Q468.75 in interest. What capital has been borrowed?"

Learn more about Interest at

brainly.com/question/25793394

#SPJ1

5 0
2 years ago
some of the apollo missions transported astronauts from earth to moon. the travel time was about 3 days and about 385,000 kilome
lord [1]
3,322.609847222222 mph. First covert miles to km. This distance is 239227.909 miles. then divide this by the number of hours which is number of days times 24. It took 3 days so it is 72 hours. After diving 239227.909/72 you get your answer of 3,322.609847222222 mph
5 0
3 years ago
Find the perimeter of a rectangular strip of board is 3.28m long and 7.5m
OLEGan [10]

Answer:

21.56 m

Step-by-step explanation:

2(3.28) + 2(7.5)

(twos represent the sides)

6.56 + 15

= 21.56 m

8 0
3 years ago
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