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Question 1123589: Can you please explain to me how a linear equation can have 2 solutions? Thanks.
Found 4 solutions by greenestamps, MathLover1, solver91311, ikleyn: Answer by greenestamps(13200) (Show Source):
You can put this solution on YOUR website!
A linear equation is an equation whose graph is a straight line.
Each point on the graph is a solution to the equation.
A line consists of an infinite number of points; so a linear equation has not only 2 solutions, but an infinite number of solutions.
Example: y = 2x (a very simple linear equation)
Choose any value for x; the corresponding y value is twice the x value. Clearly you have an infinite number of choices for the x value.
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And having written that response, I'm wondering if you meant a linear equation in one variable, like 3x+2=11.
If that is what you mean, then it is NOT possible for a linear equation to have two solutions. A linear equation in one variable always has a single solution.
Answer by MathLover1(20849) (Show Source): Answer by solver91311(24713) (Show Source): Answer by ikleyn(52781) (Show Source):
You can put this solution on YOUR website! .
The standard form of a linear equation in one unknown is
ax = b, (1)
where "a" and "b" are numbers (given constant values), x is unknown.
You may have these 3 and only 3 cases.
a) a =/= 0.
Then the equation (1) has a single solution x = .
Geometrically, it corresponds to the case when the sloped straight line y = ax intersects the horizontal line y = b at a unique point.
b) a = 0.
Then you may have two sub-cases:
b1) b = 0. Then you have INFINITELY many solutions for the equation (1): any value of x satisfies the equation 0*x = 0.
In particular, two values x= 1 and x=2 are the solutions,
and it answers the problem's question.
Geometrically, it corresponds to the case when the horizontal straight line y = 0 = 0*x coincides with the coordinate x-axis.
b2) b =/= 0. Then the equation (1) has no solution.
Indeed, in this case the left side of the equation (1) 0*x is identically equal to zero, while the right side is not zero.
Geometrically, it corresponds to the case when the horizontal straight line y = 0 = 0*x is parallel and does not coincide
with the horizontal line y = b.
The lesson to learn from this solution is THIS :
If a linear equation ax = b has two solutions, then it has infinitely many solutions.
Or in this EQUIVALENT form :
A linear equation ax = b has two solutions if and only if it has infinitely many solutions.
Corollary :
If a linear equation ax = b has two solutions, then it is DEGENERATED, i.e. has the leading coefficient zero (ZERO) at x.
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