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Math / Algebra / Grade 8 / ml8e4

One Solution, None, or All - More Practice

Read the equation left after valid simplification. Do not guess from a few test values.

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Watch the lesson | One solution, none, or all: first practice

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Expand each bracket and combine like terms. If a nonzero coefficient of x remains, solve for one value. If x cancels, a true numerical statement means all real numbers here; a false statement means no solution. Never divide by zero.

Worked example

3(x - 2) = 3x + 1 reduces to -6 = 1, so there is no solution. But 3(x - 2) = 3x - 6 reduces to -6 = -6, so every real number works. Changing one constant changes the conclusion.

Three final equations show three possibilities: three x equals twelve gives only four; six equals nine is false and gives no solution; six equals six is true and gives all real numbers after reversible simplification.
A true or false numerical statement follows from algebra applied to the original equation.
Question 1 Over the real numbers, classify -2(x + 3) = -2x + 6.
Question 2 Over the real numbers, classify 5 - (x + 2) = 3 - x.
Question 3 Which conclusion follows from 3(x - 1) = x - 9?
Question 4 Which conclusion follows from 2(x + 4) = 3x + 8?
Question 5 Over the real numbers, classify -3(2x - 1) = 3 - 6x.