y=20+5(25-(1/2)x) +(1/2).(25-(1/2)x)^2
it turns in to y=(1/8)x^2 -15x + 457,5
i have no idea how that happened, someone mind explaining? thnx!

Question

y=20+5(25-(1/2)x) +(1/2).(25-(1/2)x)^2
it turns in to y=(1/8)x^2 -15x + 457,5
i have no idea how that happened, someone mind explaining? thnx!

anonymous · Answer

$$y=20+5(25-\frac{ 1 }{ 2 }x)+(\frac{ 1 }{ 2 })(25-\frac{ 1 }{ 2}x)^{2}$$

and now use foil, remember, dont put it to decimals and
$$(25-\frac{ 1 }{ 2 }x)^2=(25-\frac{ 1 }{ 2 }x)(25-\frac{ 1 }{ 2 }x)$$

anonymous · Answer

try to simplify it now.

anonymous · Answer

i'm sorry i'm lost, where did the (1/2) go and how are there 2 (25-(1/2)x)?

anonymous · Answer

no i didnt give you the answer i was just saying that 
(25-(1/2)x)^2 is being multiplied by itself. so first expand that out and then simplify

anonymous · Answer

oh i see, now it make sense, thank you very much!

anonymous · Answer

can you do that for every bracket powered to the 2nd?

anonymous · Answer

yes, you can do that with every power greater than 1.