1) 40+30=70 (грн)
70 грн - нова ціна
1) x³+x²y-4y-4x = x²(x+y)-4(y+x) = (x+y)(x²-4) = (x+y)(x-2)(x+2)
2)x³-3y²+3x²-xy² = x²(x+3)-y²(3+x) = (x+3)(x²-y²) = (x+3)(x+y)(x-y)
<span>sin15*cos15=1/2(sin(15-15)+sin(15+15))=1/2(sin0+sin30)=2=1/2(0+1/2)=1/2*1/2=1/4
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