Can someone help me with this :/ solve using the quadratic formula: x=(-b +/-sqr(b^2 - 4ac)/(2a)
2x² + x - 1 = 0

answers in (pic)

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2x² + x - 1 = 0

a= 2 b= 1 c= -1

x = [ -b +- sqr rt( b^2 -4ac) ] / 2*a

x = -1 +- sqr rt (1 - 4 *2*-1) / 4

x1 = [ -1 + (sqr rt (1 +8)) / 4

x1 = ( -1 + sqr rt (9)) / 4

x1 = (-1 + 3) / 4

x1 = .5

x2 = (-1 -3) / 4

x2 = -4 / 4

x2 = -1

And to check that http://www.1728.org/quadratc.htm

Step-by-step explanation:

answer: 8d

step-by-step explanation:

45+5= 50+5=55+5=60

delaney would like to make a 5lb nut mixture that is 60% peanuts and 40% almonds.

she has several pounds of peanuts and several pounds of a mixture that is 20% peanuts and 80% almonds.

let 'p' represent the number of pounds of peanuts needed to make the new mixture, and  

let 'm' represent the number of pounds of the 80% almond-20% peanut mixture.

:

p + m = 5

therefore

m = (5-p)

write an equation based on the percent of peanuts

1p + .2m = .6(5)

replace m with (5-p)

p + .2(5-p) = .6(5)

p + 1 - .2p = 3

p - .2p = 3 - 1

.8p = 2

p = 2/.8

p = 2.5 lbs of peanuts required

then

5 - 2.5 = 2.5 lbs of the peanut/almond mixture required

:

a) what is the system that models this situation?

p + m = 5

1p + .2m = .6(5)