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3 years ago

What is the missing number that makes the ratios equivalent? 12:9 _:18

Mathematics

1 answer:

S_A_V [24]3 years ago

7 0

Answer:

Step-by-step explanation:

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There are two numbers. The first number minus the second number is 15. One-third of the sum of the numbers is one quarter of the

disa [49]

Answer:

So the numbers are 12 and -3.

Step-by-step explanation:

In order to solve this problem we will attribute variables to the numbers, the first one will be "x" and the second one will be "y". From the first sentence we know that the subtraction of the two numbers is equal to 15, so we have:

x - y = 15

Then the problem states that one-third of the sum of the number is equal to one quarter of the first number, so we have:

(1/3)*(x+y) = x/4

Since we now have two equations and two variables we can solve for x and y. From the first equation we have:

y = x - 15

Using this expression for the value of y in the second equation:

(1/3)*(x + x - 15) = x/4

(1/3)*(2*x - 15) = x/4

2*x - 15 = 3*x/4

2*x - 3*x/4 = 15

(8*x - 3*x)/4 = 15

5*x/4 = 15

5*x = 60

x = 60/5 = 12

y = x - 15 = 12 - 15 = -3

So the numbers are 12 and -3.

4 0

3 years ago

Read 2 more answers

Find the equation of the line . Write in slope intercept form and in standard form. (SHOW YOUR SOLUTION)

AlladinOne [14]

Answer:

1) The slope-intercept and standard forms are $y = -5\cdot x + 1$ and $5\cdot x +y = 1$ , respectively.

2) The slope-intercept form of the line is $y = \frac{5}{2}\cdot x -\frac{9}{2}$ . The standard form of the line is $-5\cdot x +2\cdot y = -9$ .

3) The slope-intercept form of the line is $y = \frac{5}{2}\cdot x + 5$ . The standard form of the line is $-5\cdot x +2\cdot y = 10$ .

4) The slope-intercept and standard forms of the family of lines are $y = \frac{2}{7}\cdot x -\frac{c}{7}$ and $2\cdot x -7\cdot y = c$ , $\forall \,c \in \mathbb{R}$ , respectively.

5) The slope-intercept form of the line is $y = 2\cdot x-7$ . The standard form of the line is $-2\cdot x +y = -7$ .

Step-by-step explanation:

From Analytical Geometry we know that the slope-intercept form of the line is represented by:

$y = m\cdot x + b$ (1)

Where:

$x$ - Independent variable, dimensionless.

$m$ - Slope, dimensionless.

$b$ - y-Intercept, dimensionless.

$y$ - Dependent variable, dimensionless.

In addition, the standard form of the line is represented by the following model:

$a\cdot x + b \cdot y = c$ (2)

Where $a$ , $b$ are constant coefficients, dimensionless.

Now we process to resolve each problem:

1) If we know that $m = -5$ and $b = 1$ , then we know that the slope-intercept form of the line is:

$y = -5\cdot x + 1$ (3)

And the standard form is found after some algebraic handling:

$5\cdot x +y = 1$ (4)

The slope-intercept and standard forms are $y = -5\cdot x + 1$ and $5\cdot x +y = 1$ , respectively.

2) From Geometry we know that a line can be formed by two distinct points on a plane. If we know that $(x_{1},y_{1})=(1,-2)$ and $(x_{2},y_{2}) = (3,3)$ , then we construct the following system of linear equations:

$m+b= -2$ (5)

$3\cdot m +b = 3$ (6)

The solution of the system is:

$m = \frac{5}{2}$ , $b = -\frac{9}{2}$

The slope-intercept form of the line is $y = \frac{5}{2}\cdot x -\frac{9}{2}$ .

And the standard form is found after some algebraic handling:

$-\frac{5}{2}\cdot x +y = -\frac{9}{2}$

$-5\cdot x +2\cdot y = -9$ (7)

The standard form of the line is $-5\cdot x +2\cdot y = -9$ .

3) From Geometry we know that a line can be formed by two distinct points on a plane. If we know that $(x_{1},y_{1})=(-2,0)$ and $(x_{2},y_{2}) = (0,5)$ , then we construct the following system of linear equations:

$-2\cdot m +b = 0$ (8)

$b = 5$ (9)

The solution of the system is:

$m =\frac{5}{2}$ , $b = 5$

The slope-intercept form of the line is $y = \frac{5}{2}\cdot x + 5$ .

And the standard form is found after some algebraic handling:

$-\frac{5}{2}\cdot x+y =5$

$-5\cdot x +2\cdot y = 10$ (10)

The standard form of the line is $-5\cdot x +2\cdot y = 10$ .

4) If we know that $a = 2$ and $b = -7$ , then the standard form of the family of lines is:

$2\cdot x -7\cdot y = c$ , $\forall \,c \in \mathbb{R}$

And the standard form is found after some algebraic handling:

$-7\cdot y = -2\cdot x +c$

$y = \frac{2}{7}\cdot x -\frac{c}{7}$ , $\forall \,c\in\mathbb{R}$ (11)

The slope-intercept and standard forms of the family of lines are $y = \frac{2}{7}\cdot x -\frac{c}{7}$ and $2\cdot x -7\cdot y = c$ , $\forall \,c \in \mathbb{R}$ , respectively.

5) If we know that $(x,y) = (3,-1)$ and $m = 2$ , then the y-intercept of the line is: