Q 38. Solve the system of equations by... [FREE SOLUTION]

91影视

Intermediate Algebra

OPENSTAX

$Math Studyset 91影视 Explanations$ Math

OER 2017 Edition 路 1346 pages

ISBN: 9780998625720

Chapter 4: Q 38. (page 386)

Solve the system of equations by substitution
$\{\begin{cases} 2 x + y = 5 \\ x - 2 y = - 15 \end{cases}$

Short Answer

Expert verified

The solution for the system of equations is,

$x = - 1 y = 7$ .

Step by step solution

Step 1. Given the information

The system of equations is,

$\{\begin{cases} 2 x + y = 5 \\ x - 2 y = - 15 \end{cases}$

Step 2. Solve the first equation for y

Solving the equation $2 x + y = 5$ for $y$

$2 x + y = 5$

$y = 5 - 2 x$

Step 3. Substituting the value of y in the equation.

Substituting $y = 5 - 2 x$ in the equation

$x - 2 y = - 15$

$x - 2 (5 - 2 x) = - 15$

$x - 10 + 4 x = - 15$

$5 x - 10 = - 15$

$5 x = - 15 + 10$

$5 x = - 5$

$x = - 5 梅 5$

$x = - 1$

Step 4. Substituting the value of x in the equation

Substituting $x = - 1$ in the equation

$y = 5 - 2 x$

$y = 5 - 2 (- 1)$

$y = 5 + 2$

$y = 7$

Step 5. Checking the solution for the equation 2x+y=5.

Substituting $x = - 1 y = 7$ in the equation

$2 x + y = 5$

$2 (- 1) + 7 = 5$

$- 2 + 7 = 5$

$5 = 5$

This is true.

Step 6. Checking the solution for the equation x-2y=-15

Substituting $x = - 1 y = 7$ in the equation

$x - 2 y = - 15$

$- 1 - 2 (7) = - 15$

$- 1 - 14 = - 15$

$- 15 = - 15$

This is true.

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91影视

Solve the system of equations by substitution
$\{\begin{cases} 2 x + y = 5 \\ x - 2 y = - 15 \end{cases}$

Short Answer

Step by step solution

Step 1. Given the information

Step 2. Solve the first equation for y

Step 3. Substituting the value of y in the equation.

Step 4. Substituting the value of x in the equation

Step 5. Checking the solution for the equation 2x+y=5.

Step 6. Checking the solution for the equation x-2y=-15

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91影视

Solve the system of equations by substitution2x+y=5x-2y=-15

Short Answer

Step by step solution

Step 1. Given the information

Step 2. Solve the first equation for y

Step 3. Substituting the value of y in the equation.

Step 4. Substituting the value of x in the equation

Step 5. Checking the solution for the equation 2x+y=5.

Step 6. Checking the solution for the equation x-2y=-15

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Mechanics Maths

Discrete Mathematics

Theoretical and Mathematical Physics

Pure Maths

Calculus

Probability and Statistics

Study anywhere. Anytime. Across all devices.

Solve the system of equations by substitution
$\{\begin{cases} 2 x + y = 5 \\ x - 2 y = - 15 \end{cases}$