Straight

Hello Guest,

you need to check your question very carefully. I don't know what you mean...

Maybe you mean this:

440 : 8 = 55,

440 * 8 = 3520,

ggT (440; 8) = 8,

kgV (440; 8) = 440.

Straight

Hello Guest,

you're answer is right.

You can put this in thw calculator.

Do you actually need help?

Straight

Hello AnxiousLlama,

I am problably too late and I'm not sure, but still I give a try:

$\binom{n-1}{r-1}+\binom{n-1}{r}$ 

order the terms using the commutative law

$\binom{n-1}{r}+\binom{n-1}{r-1}$

simplify with the Pascal's triangle $\binom{n}{k}+\binom{n}{k-1}=\binom{n+1}{k}$ to 

$\binom{n}{r}$ so it's true.

Straight

Hello Guest,

here are my steps:
 

rewrite the system of equations to:

$4x+5y=7$ 

$13x+5y=7$ ,

$4x+5y=7$

$-13x+5y=-7$,

$-9x=0$,

$x=0$,

$4*0+5y=7$,

$y=\frac{7}{5}$,

$(x,y)=(0,\frac{7}{5})$,

$4*0+5*\frac{7}{5}=13*0+5*\frac{7}{5}=7$,

so $7=7=7$ (it's true), finally is the solution:

$(x,y)=(0,\frac{7}{5})$

Straight

Hello Guest,

I don't understand your question, but I can say:

0.2 = 1/5 or 0.2 = 20%

Straight

Hello Melody,

maybe I'm just doing my method, so I am not having problems, 

thanks anyway for your interest and understanding.

Straight

Show your steps, please.

Straight

Hello Guest,

here's the answer:

$3x+2y+xy=115+7x$ ,

$\frac{d}{dx}(3x)+\frac{d}{dx}(2y)+\frac{d}{dx}(xy)=\frac{d}{dx}(115)+\frac{d}{dx}(7x)$,

$3+\frac{d}{dx}(2y)+\frac{d}{dx}(xy)=\frac{d}{dx}(115)+\frac{d}{dx}(7x)$,

$3+\frac{d}{dy}(2y)*\frac{dy}{dx}+\frac{d}{dx}(xy)=\frac{d}{dx}(115)+\frac{d}{dx}(7x)$ ,

$3+\frac{d}{dy}(2y)*\frac{dy}{dx}+\frac{d}{dx}(x)*y+x*\frac{d}{dx}(y)=\frac{d}{dx}(115)+\frac{d}{dx}(7x)$ ,

$3+\frac{d}{dy}(2y)*\frac{dy}{dx}+\frac{d}{dx}(x)*y+x*\frac{d}{dx}(y)=0+\frac{d}{dx}(7x)$ ,

$3+2*\frac{dy}{dx}+\frac{d}{dx}(x)*y+x*\frac{d}{dx}(y)=0+\frac{d}{dx}(7x)$ ,

$3+2*\frac{dy}{dx}+1y+x*\frac{d}{dx}(y)=0+\frac{d}{dx}(7x)$ ,

$3+2*​​\frac{dy}{dx}+1y+x*\frac{d}{dx}(y)=0+\frac{d}{dx}(7x)$ ,

$3+2*\frac{dy}{dx}+1y+x*\frac{d}{dy}(y)*\frac{dy}{dx}=0+\frac{d}{dx}(7x)$ ,

$3+2*\frac{dy}{dx}+1y+x*\frac{d}{dy}(y)*\frac{dy}{dx}=\frac{d}{dx}(7x)$ ,

$3+2*\frac{dy}{dx}+1y+x*\frac{d}{dy}(y)*\frac{dy}{dx}=7$ ,

$3+2*\frac{dy}{dx}+y+x*\frac{d}{dy}(y)*\frac{dy}{dx}=7$ ,

$3+2*\frac{dy}{dx}+y+x*1*\frac{dy}{dx}=7$ ,

$3+2*\frac{dy}{dx}+y+x*\frac{dy}{dx}=7$ ,

$2*\frac{dy}{dx}+x*\frac{dy}{dx}=7-3-y$ ,

$(2+x)*\frac{dy}{dx}=7-3-y$ ,

$(2+x)*\frac{dy}{dx}=4-y$ ,

$\frac{dy}{dx}=\frac{4-y}{2+x}$ ,

so the solution is: $\frac{dy}{dx}=\frac{4-y}{2+x}$ .

Straight