Question

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a)5(x-1)(x+2)-5(x+1)(x-2)

b)4(x-1)(x+1)-(2(x+1)) 2

c)-3 (2-x)(x-1)-(x-2) 2

d)4 (a+b+1) (2-b) - (2b+a)(2-2b)

Answer 1

a/  5(x-1)(x+2)-5(x+1)(x-2)= 5[(x-1)(x+2)-(x+1)(x-2)]=5[ x²+2x-x-2-(x²-2x+x-2]=

      5[x²+x-2-x²+x+2]=5·2x=10x

 

b/  4(x-1)(x+1)-[2(x+1)]²=4(x-1)(x+1)-4(x+1)²=4(x²-1)-4(x²+2x+1)=4[x²-1-(x²+2x+1]=4(x²-x²-1-2x-1)=4(-2x-2)=-8(x+1)   lub

   

      4(x-1)(x+1)-4(x+1)²=4(x+1)[(x-1)-(x+1)]=4(x+1)(x-1-x-1=4(x+1)·(-2)=-8(x+1)

 

c/ -3(2-x)(x-1)-(x-2)²=-3·-(x-2)(x-1)-(x-2)²=3(x-2)[(x-1)-(x-2)]=3(x-2)(x-1-x+2)=3(x-2)(1)=3(x-2)

 

d/  4(a+b+1)(2-b)-(2b+a)(2-2b)= 4(2a+2b+2-ab-b²-b)-(4b+2a-4b²-2ab)=8a+8b+8-4ab-4b²-4b-4b-2a+4b²+2ab=6a-2ab+8