Question

responda (a+4).(a-5)​

Answer 1

a^2-5a+4a-20
a^2-a-20=0
▲=b^2-4*a*c
▲=(-1)^2-4*1*(-20)
▲=1-4*(-20)
▲=1+80
▲=81

x= -b+-√ ▲/2*a
x= -(-1)+-√81/2*1
x=1+-9/2
x’= 1+9/2= 10/2= 5
x”= 1-9/2= -8/2= -4