Question

1. X2 - 10 X + 21
2. X2 - X - 90
3. -X2 - 8 X + 20
4. 4X2 + 44 X + 120
5. -3X2 + 24 X - 63
6. 2Х2+Х-3
7. Х2-26Х+120
8. 10Х2-11Х+3
9. Х2-24Х-56
10. 4Х2-3Х+1
11. 9Х2-12Х+4
12. Х2-18Х+77
СРОЧНОООООООО!!!!!!!!!!!!! ЗА РАНЕЕ СПАСИБО <3

Answer 1

$x^2-10x+21=left(x^2-3xright)+left(-7x+21right) = xleft(x-3right)-7left(x-3right) =left(x-3right)left(x-7right)\\x^2-x-90=left(x^2+9xright)+left(-10x-90right)=xleft(x+9right)-10left(x+9right)=left(x+9right)left(x-10right)\\-x^2-8x+20=-left(x^2+8x-20right)=-(left(x^2-2xright)+left(10x-20right))=-(xleft(x-2right)+10left(x-2right))=-left(x-2right)left(x+10right)$

$4x^2+44x+120=4left(x^2+11x+30right)=4(left(x^2+5xright)+left(6x+30right))=4(xleft(x+5right)+6left(x+5right))=4left(x+5right)left(x+6right)\\-3x^2+24x-63=-3left(x^2-8x+21right)\\2x^2+x-3 = left(2x^2-2xright)+left(3x-3right) = 2xleft(x-1right)+3left(x-1right)=left(x-1right)left(2x+3right)$$x^2-26x+120 = left(x^2-6xright)+left(-20x+120right) =xleft(x-6right)-20left(x-6right)=left(x-6right)left(x-20right)\\10x^2-11x+3=left(10x^2-5xright)+left(-6x+3right)=5xleft(2x-1right)-3left(2x-1right)=left(2x-1right)left(5x-3right)\\9x^2-12x+4 =left(3xright)^2-2cdot :3xcdot :2+2^2=left(3x-2right)^2$

$x^2-18x+77=left(x^2-7xright)+left(-11x+77right)=xleft(x-7right)-11left(x-7right)=left(x-7right)left(x-11right)$