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3 years ago

The difference of the square of a number and 28 is equal to 3 times that number

Mathematics

1 answer:

Pepsi [2]3 years ago

5 0

Answer:

- 4, 7

Step-by-step explanation:

Let the required number be x.

Therefore, according to the given condition:

${x}^{2} - 28 = 3x \\ {x}^{2} - 3x - 28 = 0 \\ {x}^{2} - 7x + 4x - 28 = 0 \\ x(x - 7) + 4(x - 7) = 0 \\ (x - 7)(x + 4) = 0 \\ x - 7 = 0 \: or \: x + 4 = 0 \\ x = 7 \: or \: x = - 4 \\$

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Last year the depth of the river was 4.2 feet deep. This year it dropped 25%. Find the depth of the river this year to cross it.

Novosadov [1.4K]

Answer:

The river is 3.15 feet deep.

Step-by-step explanation:

First let's recognize what we need to find: the depth of the river

We know last year the river was 4.2 feet deep, but it dropped 25%. This means we also need to find how much it dropped. To find this, we need to know what 25% of 4.2 is. Write an equation for this.

y = 25% of 4.2

y = 0.25 • 4.2

y = 1.05

This means that the river dropped 1.05 feet. To know its depth now, we need to subtract 1.05 from 4.2. Write an equation for this.

d = 4.2 - 1.05

d = 3.15

The river is 3.15 feet deep.

Hope this helps!

4 0

3 years ago

123°

zhuklara [117]

Answer:

Supplementary 19

180-123=57

57÷3=19

Check:

123+57=180

8 0

3 years ago

Help please please please please

Papessa [141]

Answer:

A. {x| x≠ 0}

Step-by-step explanation:

As per the graph, the domain can get any value but zero

Correct option is A. {x| x≠ 0}

6 0

3 years ago

List 75% , 1/6 , 3/8 , and 0.625 from least to greatest . :) PLZ HELP

alexandr1967 [171]

1/6, 2/8, .625, 75% :)))

6 0

3 years ago

Read 2 more answers

Just Need A Few Questions Answered To Finish My Quiz, Any Help Would Be Much Appreciated.

kvv77 [185]

Given the triangle

PQR

with points

P(8,0)

Q(6,2)

R(-2,-4)

And the triangle

P'Q'R'

with points

P'(4,0)

Q'(3,1)

R'(-1,-2)

Part A. Scale factor

Using the vertex

P( 8, 0)

P'(4,0)

the dilatation factor is given by

$\frac{4}{8}=\frac{1}{2}$

The triangle has a dilatation factor of 1/2

Part B:

P''Q''R'' after using P'Q'R' reflected about the y axis

to make a reflection over the y axis

coordinates (x,y) turn into coordinates (-x,y)

as follows

$P^{\prime}(4,0)\rightarrow P^{\prime\prime}(-4,0)$ $Q^{\prime}(3,1)\rightarrow Q^{\prime\prime}(-3,1)$ $R^{\prime}(-1,-2)\rightarrow R^{\prime\prime}(1,-2)$

Then triangle P''Q''R'' has coordinates

P''(-4,0)

Q''(-3,1)

R''(1,-2)

Part C:

PQR is congruent to P''Q''R''?

Congruent triangles are triangles that have the same size and shape. This means that the corresponding sides are equal and the corresponding angles are equal.

Then the triangles are not congruent

8 0

1 year ago