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2 years ago

How do you know whether to add or subtract when using the distributive property to multiply?

1 answer:

6 0

Distributive property is characterized by the use of parenthesis, wherein you distribute the outside number to each term inside the parenthesis by multiplication. You'll just have to copy the operation inside the parenthesis as it is, whether addition or subtraction. For example,

3(10+4-3) = 3(10) + 3(4) - 3(3) = 33

You might be interested in

The equation y =

-Dominant- [34]

Answer:

The constant of proportionality k = 12

Hence, option A is true.

Step-by-step explanation:

We know that when 'y' varies directly with 'x', we get

y ∝ x

y = kx

Where 'k' is called the constant of proportionality.

In our case,

The given equation is

y = 12x

comparing with the equation y = kx, we can say

k = 12 which is the constant of proportionality.

Therefore, we conclude that:

The constant of proportionality k = 12

Hence, option A is true.

6 0

2 years ago

The focus of a parabola is (0, -3) and the directrix is y = 3. What is the equation of the parabola?

OleMash [197]

Answer:

The equation of the parabola is $y = -12\cdot x^{2}$ .

Step-by-step explanation:

Since the directrix is of the form $y = a$ , the parabola is vertical. The vertex of the parabola ( $V(x,y)$ ) is the midpoint between the focus ( $F(x,y)$ ) and a point of the directrix ( $P(x,y)$ ), that is to say:

$V(x,y) = \frac{1}{2}\cdot F(x,y) + \frac{1}{2}\cdot P(x,y)$ (1)

If we know that $F(x,y) = (0, -3)$ and $P(x,y) = (0, 3)$ , then the coordinates of the vertex of the parabola:

$V(x,y) = \frac{1}{2}\cdot (0, -3) + \frac{1}{2}\cdot (0, 3)$

$V(x,y) = (0, 0)$

The vertex factor ( $p$ ) is the distance of the focus with respect to the vertex:

$p = \sqrt{[F(x,y)-V(x,y)]\,\bullet \,[F(x,y)-V(x,y)]}$ (2)

If we know that $F(x,y) = (0, -3)$ and $V(x,y) = (0, 0)$ , then the vertex factor is:

$p = \sqrt{0^{2}+(-3)^{2}}$

$p = -3$

The equation of the parabola in the vertex form is described below:

$y - k = 4\cdot p \cdot (x-h)^{2}$ (3)

Where:

$x$ - Independent variable.

$y$ - Dependent variable.

$h, k$ - Coordinates of the vertex.

If we know that $(h,k) = (0, 0)$ and $p = -3$ , then the equation of the parabola is $y = -12\cdot x^{2}$ .

6 0

1 year ago

Write the equation of the line for the following table of values.

Luda [366]

Answer:

We conclude that the equation of the line is:

$y = 5x + 1$

Step-by-step explanation:

The slope-intercept form of the line equation

$y = mx+b$

where

m is the slope

b is the y-intercept

Given the data table

x -3 -5 -7 -9 -11

y -16 -26 -36 -46 -56

From the table taking two points

(-3, -16)

(-5, -26)

Determining the slope between (-3, -16) and (-5, -26)

$\mathrm{Slope}=\frac{y_2-y_1}{x_2-x_1}$

$\left(x_1,\:y_1\right)=\left(-3,\:-16\right),\:\left(x_2,\:y_2\right)=\left(-5,\:-26\right)$

$m=\frac{-26-\left(-16\right)}{-5-\left(-3\right)}$

$m=5$

Thus, the slope of the line is: m = 5

substituting m = 5 and (-3, -16) in the slope-intercept form of the line equation to determine the y-intercept b

$y = mx+b$

-16 = 5(-3) + b

-16 = -15 + b

b = -16+15

b = 1

Thus, the y-intercept b = 1

now substituting m = 5 and b = 1 in the slope-intercept form of the line equation

$y = mx+b$

$y = 5x + 1$

Therefore, we conclude that the equation of the line is:

$y = 5x + 1$

5 0

2 years ago

2/6 +36 Whats the answer ?

777dan777 [17]

36 2/6

do I have to explain???

4 0

2 years ago

Read 2 more answers

Matt is showing his work in simplifying (6.2 − 1.6) − 4.4 + 7.8. Identify any error in his work or reasoning. Step 1: (6.2 − 1.6

Black_prince [1.1K]

Answer:

The correct option is (d)-He wrote commutative instead of associative in Step 2.

Step-by-step explanation:

Commutative property: $a+b=b+a$

Associative property: $(a+b)+c=a+(b+c)$

Now consider the provided expression.

(6.2 − 1.6) − 4.4 + 7.8

Step 1

(6.2 − 1.6) − 4.4 + 7.8

Step 2 Use Associative property

6.2 + (−1.6 − 4.4) + 7.8

Step 3: Simplify

6.2 − 6 + 7.8

Step 4: Use commutative property

14 − 6

Step 5: Simplify

14 − 6 = 8

Hence, the wrong step is step 2. He wrote commutative instead of associative in Step 2.

Therefore, the correct option is (d)-He wrote commutative instead of associative in Step 2.

8 0

3 years ago