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3 years ago

PLEASE HELP

Mathematics

2 answers:

Alenkinab [10]3 years ago

6 0

Answer:

B. Substitute 9x for y in the first equation

Step-by-step explanation:

There are various ways of solving a system of linear equations:

- Graphing

- Substitution

- Elimination

Here, given that we have two equations that are equal to y in terms of x, we can use substitution and essentially either plug in the expression (7x + 3) in for y in the second equation or plug in the expression (9x) in for y in the first equation.

Look at the answer choices: only B matches, so it's the correct answer.

Olegator [25]3 years ago

3 0

Step-by-step explanation:

Step 1: Find the most reasonable step

Option A: It doesn't make sense because that will not help us solve the system of equation.

Option B: This option makes sense because you can then solve for x.

Option C: It doesn't make sense because that will not help us solve the system of equation.

Option D: It doesn't make sense because that will not help us solve the system of equation.

Answer: Option B

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If BC = 5, DE = 9, and AB = 4, what is the length of AD? 7 8 7.2 7.5

steposvetlana [31]

There are two triangles here: ABC and ADF. These triangles are similar, and thus proportional. So, we can set up a proportion between the left side of each triangle and the base of each triangle.

AB / AD = BC / DE

4 / (4 + BD) = 5 / 9

---AD is made up of AB and DB. We know AB, but not BD, so we need to find its value to find the length of AD.

5(4 + BD) = 9 x 4

20 + 5BD = 36

5BD = 16

BD = 3.2

AD = AB + BD

AD = 4 + 3.2

AD = 7.2

Hope this helps!

8 0

3 years ago

Write the number 33×10^-3 in scientific notation

cluponka [151]

Answer:

Step-by-step explanation:

33×10^-3 is equivalent to 33/1000, or 0.033.

This, in turn, is equivalent to 3.3×10^(-2) (which is in scientific notation)

4 0

3 years ago

Inverse function of y = -2x3+1

Ymorist [56]

The answer to your question is y=-5

6 0

3 years ago

If a1=7 and an=an-1+5 than find the value of a5 .

Katyanochek1 [597]

Answer:

a₅=27.

Step-by-step explanation:

1) according to the condition the given subsequence is arithmetic sequence. It means, the a₁=7 and d=5, then

2) a₅=a₁+4*d; => a₅=7+4*5=27.

4 0

2 years ago

A submarine dives 300 feet every 2 minutes, and 6,750 feet every 45 minutes. Solve for A and

Gelneren [198K]

A: To find the rate in feet per minute, we can use the information given.
Every two minutes, the submarine dives 300 feet. So
$\frac{300feet}{2minutes} = 150 \frac{feet}{minute}$ .
In order to confirm that our rate is correct, we can use the second set of information given.
$\frac{6750feet}{45minutes}$ = $150 \frac{feet}{minute}$ .
Since we know that the rate is 150 feet per minute, we can multiply it by any number of minutes and get the answer of how deep the submarine is. We can use a variable x to represent the number of minutes and y to represent the depth in feet.
$y=150x$
There's our equation.
B: It would be more reasonable to use an equation with the rate feet per minute because it is more accurate since the time interval isn't too big.

3 0

3 years ago