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Given: x/4=3/11x4=311
Our target is to have xx on its own on one side of the equals and all the numbers on the other side
color(red)("First principles method")First principles method
If we can change the 1/414bit from x/4x4 into 1 then x xx1->xx×1→x and we have solved it.
Write as
color(green)(x xx1/4=3/11)x×14=311
Multiply both sides by color(red)(4)4
color(green)(x xx1/4color(red)(xx4)color(white)("ddd")=color(white)("ddd")3/11color(red)(xx4))x×14×4ddd=ddd311×4
color(green)(color(white)("dd")x xx(color(red)(4))/4color(white)("dddd")=color(white)("ddd")(3color(red)(xx4))/11)ddx×44dddd=ddd3×411
color(white)("dd")x xx1color(white)("ddddd") =color(white)("ddd")12/11ddx×1ddddd=ddd1211
x=12/11x=1211
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color(red)("Shortcut method ")Shortcut method
color(brown)("Basically this is just remembering what happens with first principles")Basically this is just remembering what happens with first principles
Consider the 4 from x/4x4
This is x-:4x÷4 so move the 4 to the other side of the equals and use the opposite action to divide. Which is multiply.
So x/4=3/11 color(white)("d")->color(white)("d")color(white)("d")x=3/11xx4x4=311d→ddx=311×4
x=12/11x=1211