/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 15 Solve each system by substitutio... [FREE SOLUTION] | 91Ó°ÊÓ

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Solve each system by substitution. $$\begin{aligned} &-2 x=6 y+18\\\ &-29=5 y-3 x \end{aligned}$$

Short Answer

Expert verified
(x, y) = (3, -4)

Step by step solution

01

Solve for one variable

First, solve the first equation for one variable. Start with \(-2x = 6y + 18 \) and solve for \(x\): \(-2x - 6y = 18 \), thus \(x = -3y - 9 \).
02

Substitute the expression into the second equation

Substitute the expression \(x = -3y - 9\) into the second equation \(-29 = 5y - 3x\): \(-29 = 5y - 3(-3y - 9)\).
03

Simplify the substitution

Simplify the substituted equation: \(-29 = 5y - 3(-3y) - 3(-9)\), which simplifies to \(-29 = 5y + 9y + 27\).
04

Combine like terms

Combine like terms in the equation: \(-29 = 14y + 27\).
05

Solve for the variable y

Solve for \(y\): Subtract 27 from both sides: \(-56 = 14y\), then divide both sides by 14: \(y = -4\).
06

Substitute y back into the expression for x

Substitute \(y = -4\) back into the expression \(x = -3y - 9\): \(x = -3(-4) - 9\), which simplifies to \(x = 3\).
07

Solution to the system

The solution to the system of equations is \(x = 3\) and \(y = -4\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

substitution method
The substitution method is one of the ways to solve a system of linear equations. This method involves solving one of the equations for one variable and then substituting this expression into the other equation.
This allows you to find the value of one variable, which can then be substituted back into the expression to find the value of the other variable.
By breaking down the equations this way, you effectively reduce a system of equations into a simpler, single-variable equation.
This method is particularly useful because it transforms a difficult problem into a series of simpler steps.
By focusing first on one variable and substituting it into the second equation, you progressively narrow down the possible solutions until you can find the exact values for both variables.
solving linear equations
Solving linear equations is a fundamental skill in algebra. A linear equation is any equation that can be written in the form of ax + by = c, where a, b, and c are constants.
To solve a linear equation, the goal is to isolate the variable on one side of the equation.
Here's a simple approach to solve:
  • Combine like terms on both sides of the equation.
  • Use inverse operations to isolate the variable term (addition/subtraction).
  • If the variable has a coefficient, divide both sides of the equation by that coefficient to solve for the variable.
In the context of the substitution method, once you've isolated one variable, you substitute this expression into the other equation.
This will give you a linear equation with a single variable, which can be solved to find the value of that variable.
solution of system
The solution of a system of linear equations involves finding the values of the variables that satisfy both equations simultaneously. In simpler terms, you're finding the point where the two lines represented by the equations intersect.
To verify your solution, you should substitute the values of the variables back into the original equations.
Here’s a quick rundown using the given exercise:
  • First, you solve one equation for one variable and substitute it into the second equation (Substitution Method).
  • Next, simplify and solve this single-variable equation to find the value of the variable (like solving linear equations).
  • After that, substitute this value back into the expression you found for the other variable.
  • The values you get for both variables form the solution to your system of equations.
For the given problem, we found the solution as x = 3 and y = -4. This means the point (3, -4) satisfies both original equations, making it the solution to the system.

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Most popular questions from this chapter

Use Cramer's rule to solve each system of equations. If \(D=0,\) use another method to determine the solution set. $$\begin{aligned} -2 x-2 y+3 z &=4 \\ 5 x+7 y-z &=2 \\ 2 x+2 y-3 z &=-4 \end{aligned}$$

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Use the determinant theorems to find the value of each determinant. $$\left|\begin{array}{rrrr} 3 & -6 & 5 & -1 \\ 0 & 2 & -1 & 3 \\ -6 & 4 & 2 & 0 \\ -7 & 3 & 1 & 1 \end{array}\right|$$

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