Question

Solve:
6x2 – 15x = 0
a) x= 2 or x= 5
b) x= 2 or x = 5.5
c)
x= 0 or x= 2.5



d) x= 0 or x= 2

Answer 1

hint... rewrite it like:
\[\LARGE 6x^2-15x+0=0 \]

now use the quadratic fomula:
\[\LARGE x_{1/2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\]

you have:

\[\LARGE \underbrace{6}_{a}x^2\;\underbrace{-15}_{b}\;x\underbrace{+0}_{c}=0 \]

Answer 2

substitute ...

Answer 3

I think that it's simpler this way:
\[6x^2-15x=0\]\[x(6x-15)=0\] wich is true if x = 0 or \[6x-15 = 0\rightarrow x={15\over6}=2.5\]

Answer 4

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