1. а^2/a(a-3) = a/a-3
2. (x-y)(x+y)/x(x+y)=x-y/x
3. К общему знаменателю (x+y)(x-y), т.е.((x+y)^2 - (x-y)^2)/(x-y)(x+y)=(x^2-2xy+y^2-x^2+2xy-y^2)/(x-y)(x+y)=1/(x-y)(x+y)
D=b^2-4ac=64-4×1×15=64-60=4
X1=(8+2)/2=5
X2=(8-2)/2=3
Ответ:3;5
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РАССКРОЙТЕ СКОБКИ.
А) Х+(У-Z) = X + Y - Z
<span>Б)M-(N-P) = M - N + P</span>
<span>В)A+(B-C+D) = A + B - C + D</span>
<span>Д)A-(B+C+D) = A - B -C - D</span>
<span>Е)(A-B)+(C-D) = A - B + C - D</span>
<span>Ж)(M-N)-(K-T) = M - N - K + T</span>