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Secondary 1 | Maths
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I don't know what's wrong here.
Date Posted: 3 years ago
Views: 346
Hi there! For this question, one misconception would be that fractions with algebra in the numerator and denominator can simply be interpreted as equal to a value on a fraction with whole numbers. For example, even though the fractions 15/25 and 3/5 are equal to one another, the steps in this question would also mean that we can equate 15=3 and 25=5, which is not true. Hence, instead of looking at the values as simply equal, fractions are just proportions or ratios of values compared to one another. Hence, to solve the equation, we should multiply (5x+1) with 3 and (7x+1) with 2, and equate these teo new values with one another. This should give us 15x+3= 14x+2. From there, you can solve for x.:)
ah,i see.ok,thank you :D
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Firstly, you cant directly compare denominatprs and numerators like that.
Why?
Given a valid equation 2/3 = 4/6, can i say that 2 = 4 and 3 = 6? Obviously, we cant do that. So when algebra is mixed in to the equation, we cant for sure say that when the correct unknowns are added in, the numerators and denominators will be the same. So never assume that they will be the same, so always cross multiply.
Why?
Given a valid equation 2/3 = 4/6, can i say that 2 = 4 and 3 = 6? Obviously, we cant do that. So when algebra is mixed in to the equation, we cant for sure say that when the correct unknowns are added in, the numerators and denominators will be the same. So never assume that they will be the same, so always cross multiply.
oh,i see.thanks :)
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