Question

Wtf am I doing wrong???

Using the quadratic formula:

X^2-8x-20=0

-(-8)+ or - the square root of -8^2-4(1)(-20) over 2(1)

8 + or - the square root of -64 + 80 over 2

8 + or - the square root of 16 over 2

8+4 over 2 = 6

8-4 over 2 = 2.

These solutions are incorrect. I dont know what I'm doing wrong here.​

Answer 1

b^2 - 4ac

64 - (-80)

64 + 80

144

_/ 144

12

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Answer 2

Answer:

Step-by-step explanation:

the solution is of Course incorrect. this is because(-8)^2 = 64 and not

- 64. the minus sign disappears when you square.

Delta = 64 + 80 = 144 and

sqrt(Delta) = sqrt(144) = 12

the roots would then be

x1 = (8 + 12)/2 = 20/2 = 10

and

x2 = (8 - 12)/2 = - 4/2 = - 2.