Is the equation correct?
a2+9a−20=(a+4)(a−5) a^2+9a-20=(a+4)(a-5) a2+9a−20=(a+4)(a−5)
We solve the right side of the equation using the extended distributive property:(a+b)×(c+d)=ac+ad+bc+bd (a+b)\times(c+d)=ac+ad+bc+bd (a+b)×(c+d)=ac+ad+bc+bd
(a+4)(a−5)=a2−5a+4a−20 (a+4)(a-5)=a^2-5a+4a-20 (a+4)(a−5)=a2−5a+4a−20
a2−a−20 a^2-a-20 a2−a−20
That is, answer D is the correct one.
No, −a -a −a instead of +9a +9a +9a