SOLUTION: Use algebraic rules of equations to predict the solution type to the system of equations f(x)={x+y=-4 y=2x-1

Algebra ->  Systems-of-equations -> SOLUTION: Use algebraic rules of equations to predict the solution type to the system of equations f(x)={x+y=-4 y=2x-1      Log On


   



Question 1203037: Use algebraic rules of equations to predict the solution type to the system of equations
f(x)={x+y=-4 y=2x-1

Found 3 solutions by josgarithmetic, Theo, ikleyn:
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
Exactly ONE solution

system%28x%2By=-4%2Cy=2x-1%29

system%28y=-x-4%2Cy=2x-1%29
You can decide what rules you need, but two lines intersecting at exactly one single point. Exactly ONE solution.

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
here's what i get.
your equations that need to be solve simultaneously are:
x + y = -4
y = 2x - 1
we'll use the substitution method.
in the first equation, replace y with 2x - 1 from the second equation to get:
x + 2x - 1 = -4
add 1 to both sides of the eeuation and combine like terms to get:
3x = -3
solve for x to get x = 1-1
in the second equation, replace x with -1 and solve for y to get:
y = 2*-1 - 1 = -3
your solution to this equation is x = -1 and y = -3
replace x with -1 and y with -3 in both equations to ge:
x + y = -4 becomes -1 + -3 = -4 which becomes -4 = -4 which is true.
y = 2x - 1 becomes -3 = 2*-1 - 1 which becomes -2 -1 = -3 which becomes -3 = -3 which is true.
both equations are true when x = -1 and y = -3.
the graph of these equations is shown below.




A system of simultaneous linear equations can have either: one unique solution, infinitely many solutions or no solutions.

from a graphical standpoint, the unique solution is where the lines intersect; infinitely many solution are when the lines are identical, i.e. both equations form the same equivalent equation which generates the same line for both; no solutions are whn the lines are parallel to each other.

theee are ptjer waus to describe the solutions as noted in the following reference.
https://ionamaths.weebly.com/uploads/1/4/2/0/14204419/consistencyanddependency.pdf

i think that about covers it.
let me know if you need more.
theo


Answer by ikleyn(52775) About Me  (Show Source):
You can put this solution on YOUR website!
.

How the problem is formulated, it is either bad translation or bad unprofessional composition,
or a copy-paste from a bad source.

It does not sound as a right Math composition.

The first wish when reading this post, is to plug the ears with cotton so that do hear nothing.