Solve systems using method of substitution, Algebra

Assignment Help:

Example   Solve following systems.

(a)    3x - y = 7

                2x + 3 y = 1

Solution

Thus, it was the first system that we looked at above.  Already we know the solution, although it will give us a possibility to verify the values that we wrote down for the solution.

Now, the method says that we have to solve out one of the equations for one of the variables.  Which equation we select and which variable that we select is up to you, however usually it's best to pick an equation & variable which will be easy to deal with. It means we should try to ignore fractions if at all possible.

In this case it seem like it will be actually easy to solve the first equation for y thus let's do that.

                                              3x - 7 = y

 Substitute this into the second equation.

                   2 x + 3 (3x - 7 ) = 1

It is an equation in x which we can solve so let's do that.

2x + 9 x - 21 =1

11x = 22

x = 2

Thus, there is the x portion of the solution.

At last, do not forget to go back and determine the y portion of the solution. It is one of the more common mistakes students make in solving out systems.  To so it we can either plug the x value in one of the original equations & solve for y or we can only plug it into our substitution which we found in the initial step. That will be simple so let's do that.

                                          y = 3x - 7 = 3 ( 2) - 7 = -1

Thus, the solution is x = 2 and y = -1 as we noted above.


Related Discussions:- Solve systems using method of substitution

Scientific notation, answer in scientific notation correct to the ten thous...

answer in scientific notation correct to the ten thousandths 471,598,000,000

True inequality, We have to give one last note on interval notation before ...

We have to give one last note on interval notation before moving on to solving inequalities. Always recall that while we are writing down an interval notation for inequality that t

Quadratic equations, Before proceeding with this section we have to note th...

Before proceeding with this section we have to note that the topic of solving quadratic equations will be covered into two sections. It is done for the advantage of those viewing t

Geometric Sequences, How do you write an exponential decay function to mode...

How do you write an exponential decay function to model a situation?

Quadratic, how to get the perfect square

how to get the perfect square

Differential equations, verify Liouville''s formula for y'''' - y'''' -y'' ...

verify Liouville''s formula for y'''' - y'''' -y'' + y = 0 in (0,1)

Linear equations in two variables in their graph, i need help withese two p...

i need help withese two problems: y=x+4; (-7,1) and y=-1/2x +1; (4,2)

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd