All categories

3 years ago

Which expression could be used to solve this problem?

Mathematics

2 answers:

IRISSAK [1]3 years ago

8 0

Answer:

C. 3 x (20 + 15)

Step-by-step explanation:

You have to add 20 + 15 to get 45 so the 20 + 15 goes in the (). It says how much time he has practiced in 3 days so you have to multiply the things in the () by 3 so the 3 goes out side the ().

8090 [49]3 years ago

7 0

Answer:

C. 3 × (20 + 15)

Step-by-step explanation:

If Ben practices this way every day, then the amount of time should be the same.

20 minutes of song practice, 15 minutes of scale practice.

20+15=35

multiply the 35 minutes per day by three

35 times 3 equals 105

So the answer is C.

3 × (20 + 15)

3(35)=105

You might be interested in

Fencing costs $25.80 per yard. How much does it cost to enclose two adjacent rectangular pastures as shown?

Westkost [7]

13.97 bye

Thank the very best friend and

8 0

2 years ago

Read 2 more answers

Neeeeed helpppppp please

MissTica

Answer:

Scale factor = 7

Step-by-step explanation:

Dilation with scale factor to map HEFG to DABC will be,

Scale factor = $\frac{\text{Dimension of Image DABC}}{\text{Dimension of preimage HEFG}}$

= $\frac{\text{Length of CD}}{\text{Length of GH}}$

Length of CD = Distance between two points C(0, -7) and D(-7, 0)

= $\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

= $\sqrt{(-7-0)^2+(0+7)^2}$

= $\sqrt{98}$

= $7\sqrt{2}$

Length of GH = Distance between G(0, -1) and H(-1, 0)

= $\sqrt{(-1-0)^2+(0+1)^2}$

= $\sqrt{2}$

Scale factor = $\frac{7\sqrt{2} }{\sqrt{2} }$

= 7

6 0

3 years ago

3х - 30 = у 7y - 6 = 3х

mars1129 [50]

Answer:

Step-by-step explanation:

This one is simple substitution... at least, substitution is the easiest method. The first equation is 3x – 30 = y and the second is 7y – 6 = 3x

As I look, I see 3 ways to use substitution to solve this:

substitute 7y – 6 for 3x
substitute 3x – 30 for y
solve 3x – 30 = y for 3x and make it equal to 7y – 6

We're going to only use 1 method for the sake of time. Try the other two on your own. Assuming you don't make any mistakes, they will work.

Method 1:

3x – 30 = y

7y – 6 = 3x — initial system of equations

7y – 6 – 30 = y — substitute 7y – 6 for 3x

7y – 6 – 30 = y — marking like terms, bold for constants, underlined for variables

7y – 36 = y — combining the constants and simplifying

Here, you could diverge into multiple paths: add 36 to both sides, subtract y from both sides, divide by 6 OR subtract 7y from both sides and divide by –6 . For the sake of time, I'm subtracting 7y, though I don't like dealing with negatives.

7y – 7y – 36 = y – 7y — subtract 7y from both sides

–36 = –6y — simplify

–36 ÷ –6 = –6y ÷ –6 — divide by –6 on both sides

y = 6 — simplify

Again, we can diverge here: substitute y into 3x – 30 = y or substitute y into 7y – 6 = 3x

I'm going to choose 3x – 30 = y but it will work either way, should you take the time (if you have it) to chase down every path this problem can take.

3x – 30 = y — initial equation

3x – 30 = 6 — substitute 6 for y

3x – 30 + 30 = 6 + 30 — add 30 to both sides to isolate 3x

3x = 36 — simplify the expression

3x ÷ 3 = 36 ÷ 3 — divide both sides by 3 to isolate x

x = 12 — simplify

So, we have x = 12 and y = 6 . We know they work for 3x – 30 = y but not if they work for 7y – 6 = 3x . Let's substitute those in to see if (12, 6) really is the solution point.

7y – 6 = 3x — original equation

7(6) – 6 ≟ 3(12) — substitute 6 for y and 12 for x

42 – 6 ≟ 36 — simplify by multiplying

36 = 36 ✔ — simplify by combining like terms on left side

Success! It works! We have found our solution!

I hope this helps increase your understanding of the concept. Have a great day!

8 0

3 years ago

I need help on what to put in the boxes.

Leona [35]

Just divide the y numbers by the x numbers and that's it

7 0

3 years ago

What is the value of f(-4)?

Ghella [55]

Given is a piecewise function which follows different expressions according the the value of input x.

Given $f(x)=\left \{ {{-10, \;if \;x2} } \right.$

It says to find f(-4) i.e. the value of function f(x) at x = -4.

At point x = -4, f(x) is x³, if -5 ≤ x ≤ 2.

So, f(-4) = (-4)³

f(-4) = -4 × -4 × -4

f(-4) = -64.

Hence, option A is correct i.e. -64.

4 0

3 years ago