Question

resolva as equações das raizes de segundo grau 
4x²-28x+40=0

Answer 1

Man, vou mandar do x1
x=$\frac{-(-28)+ \sqrt{(-28) ^{2}-4.4.40 } }{2.4}$

x= $\frac{-(-28)+ \sqrt{784-4.4.40} }{2.4}$

x= $\frac{-(-28)+ \sqrt{784+(-16).40} }{2.4}$

x=$\frac{-(-28)+ \sqrt{784-640} }{2.4}$

x=$\frac{-(-28)-12}{2.4}$

x=$\frac{16}{2.4}$

x=2

$x_{1}$ =2
$x_{2} =5$

Answer 2

a=4

b=-28

c=40

Delta=(-28)²-4*4*40

Delta=784-640

Delta=144

x=28+-12/8

x¹=28+12/8=5

x²=28-12/8=2

Ta ae resolvidinho :D