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Mathematics

Solve the following equation and check your answer:

34(7x1)(2x1x2)=x+32\dfrac{3}{4}(7x - 1)-\Big(2x -\dfrac{1-x}{2}\Big) = x + \dfrac{3}{2}

Linear Eqns One Variable

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Answer

We have:

=34(7x1)(2x1x2)=x+3221x34(4x(1x)2)=2x+3221x34(4x1+x2)=2x+3221x345x12=2x+3221x310x+24=2x+3211x14=2x+322(11x1)=4(2x+3)[By cross multiplication]22x2=8x+1222x8x=12+2[Transposing -2 to RHS and +8x to LHS]14x=14x=1414\phantom{=} \dfrac{3}{4}(7x - 1)-\Big(2x -\dfrac{1-x}{2}\Big) = x + \dfrac{3}{2} \\[1em] \Rightarrow \dfrac{21x - 3}{4}-\left(\dfrac{4x -(1 - x)}{2}\right) = \dfrac{2x + 3}{2} \\[1em] \Rightarrow \dfrac{21x - 3}{4}-\left(\dfrac{4x - 1 + x}{2}\right) = \dfrac{2x + 3}{2} \\[1em] \Rightarrow \dfrac{21x - 3}{4}-\dfrac{5x - 1}{2} = \dfrac{2x + 3}{2} \\[1em] \Rightarrow \dfrac{21x - 3 - 10x + 2}{4} = \dfrac{2x + 3}{2} \\[1em] \Rightarrow \dfrac{11x - 1}{4} = \dfrac{2x + 3}{2} \\[1em] \Rightarrow 2(11x - 1) = 4(2x + 3) \quad \text{[By cross multiplication]} \\[1em] \Rightarrow 22x - 2 = 8x + 12 \\[1em] \Rightarrow 22x - 8x = 12 + 2 \quad \text{[Transposing -2 to RHS and +8x to LHS]} \\[1em] \Rightarrow 14x = 14 \\[1em] \Rightarrow x = \dfrac{14}{14}

∴ x = 1

Check:

LHS=34(7x1)(2x1x2)LHS=34(6)(20)LHS=922LHS=52RHS=x+32RHS=1+32RHS=52\text{LHS} = \dfrac{3}{4}(7x - 1) - \left(2x - \dfrac{1-x}{2}\right) \\[1em] \phantom{\text{LHS}} = \dfrac{3}{4}(6) - \left(2 - 0\right) \\[1em] \phantom{\text{LHS}} = \dfrac{9}{2} - 2 \\[1em] \phantom{\text{LHS}} = \dfrac{5}{2} \\[2em] \text{RHS} = x + \dfrac{3}{2} \\[1em] \phantom{\text{RHS}} = 1 + \dfrac{3}{2} \\[1em] \phantom{\text{RHS}} = \dfrac{5}{2}

Hence, LHS = RHS.

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