How do you determine whether a linear system has one solution, many solutions, or no solution when given 2x-5y=3 and -4x+10y= -6?

1 Answer
Jun 11, 2018

Infinite count of solutions

Explanation:

Linear #-># straight line plot

When in the form of #y=mx+c# and you compare them.

#m -># gradient (slope)

#c -># y-intercept (point where it crosses the y-axis)

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With two linear equations

If #m# is the same in each but #c# is not the same then
#color(white)("dddd")#Parallel so do not cross thus no shared point.
#color(white)("dddd")#This is called 'no solution'.

If both #m and c# are the same
#color(white)("dddd")#One is superimposed on the other (coincidental).
#color(white)("dddd")#This is called an' infinite count of solutions'.

If both #m and c# are different then they cross once.
#color(white)("dddd")#This has just one shared point so has 1 solution.
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Given equations:

#color(white)(d.)2x-5y=3" ".....................Equation(1)#
#-4x+10y=-6" "................Equation(2)#

Manipulation gives:

#y=2/5x-3/5" ".....................Equation(1_a)#

#y=2/5x-3/5" "........................Equation(2_a)#

Both #m and c# are the same so they are coincidental.
Thus there is an infinite count if solutions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Check")#

#(-2)xxEquation(1) -> -4x+10y=-6#

This is the same as #Equation(2)#