15 23 66 10 07 bhzdzbubbvuccucuuccu
[latex]a).(2x+1) ^{2} -(3x-1)(3x-1)-(2x-3) ^{2} = \ =4 x^{2} +4x+1-(9 x^{2} -3x-3x+1)-(4 x^{2} -12x+9)= \ =4 x^{2} +4x+1-(9 x^{2} -6x+1)-4 x^{2} +12x-9= \ =4 x^{2} +4x+1-9 x^{2} +6x-1-4 x^{2} +12x-9=-9 x^{2} +22x-9[/latex] [latex]b). \ 3(a-4) ^{2} -(5a-3) ^{2} +(3a-2)(2+3a)= \ =3( a^{2} -8a+16)-(25 a^{2} -30a+9)+6a+9 a^{2} -4-6a= \ =3 a^{2} -24a+48-25 a^{2} +30a-9+9 a^{2} -4=-13 a^{2} +6a+35[/latex] [latex]c).-(2-x) ^{2} -8(1-x) ^{2} +5(1+x)(1-x)= \ =-(4-4x+ x^{2} )-8(1-2x+ x^{2} )+5(1-x) ^{2} = \ =-4+4x- x^{2} -8+16x-8 x^{2} +5-5 x^{2} =-14 x^{2} +20x-7[/latex] [latex]d).4a+(7a-1)(7a+1)-(4a-9) ^{2} -3(5a-1) ^{2} = \ =4a+49 a^{2} -1-(16 a^{2} -72a+81)-3(25 a^{2} -10a+1)= \ =4a+49 a^{2} -1-16 a^{2} +72a-81-75 a^{2} +30a-3= \ =-42 a^{2} +106a-85[/latex] [latex]e).5[(x-5) ^{2} -(3x+7) ^{2} ]-(5x-2)(5x+2)= \ =5[ x^{2} -10x+25-(9 x^{2}+42x+49]-(25 x^{2} +10x-10x-4)= \ =5( x^{2} -10x+25-9 x^{2} -42x-49)-25 x^{2} +4= \ =5(-8 x^{2} -52x-24)-25 x^{2} +4=-40 x^{2} -260x-120-25 x^{2} +4= \ -65 x^{2} -260x-116[/latex]
