Answer:
Step-by-step explanation:
(x-4) (x+10) ⇒ (x+a)(x+b)=x²+(a+b)x+ab
a=-4 , b=10
x²+(-4+10)x+-4(10)
x²+6x-40
(3x+4) (3x +5)
3(x+4/3) *3(x+5/3) ⇒ identity : (x+a)(x+b)=x²+(a+b)x+ab
a=4/3 b=5/3
3*3=9
9[x²+(4/3 +5/3)x+4/3(5/3)]
9[x²+9/3 x+20/9]
9x²+27x+20
(-3a +5b +4c)^2 ⇒
suitable identity is (a+b+c)²= a² + b² + c² + 2ab + 2bc + 2ca
a=-3a , b=5b , c=4c
9a²+25b²+16c²- 30ab +40bc - 24ca
