Question

Harry is trying to solve the equation y = 2x2 − x − 6 using the quadratic formula. He has made an error in one of the steps below. Find the step where Harry went wrong. Step 1: x equals the negative of negative 1 plus or minus the square root of the quantity negative one squared minus 4 times 2 times negative six, end quantity, all over 2 times 2. Step 2: x equals the negative of negative 1 plus or minus the square root of negative one plus forty-eight all over two times 2. Step 3: x equals the negative of negative 1 plus or minus the square root of forty-seven all over two times 2. Step 4: x equals 1 plus or minus the square root of forty-seven all over 4.

Answer 1

I believe it would be step number 2... I am not very sure...

Answer 2

Error is in step 2

Explanation:

Harry is trying to solve the equation y = 2x^2 − x − 6 using the quadratic formula. He has made an error in one of the steps below.

Step 1:
`x= (-(-1)+-√((-1)^2-4(2)(-6)) )/(2(2))`

Step 2:
`x= (-(-1)+-√(-1+48))/(2(2))`

Step 3:
`x= (-(-1)+-√(47))/(2(2))`

Step 4:
`x= (1+-√(47))/(4)`

Quadratic formula is

`x= (-(b)+-√((b)^2-4(a)(c)) )/(2(a))`

From the given equation a= 2, b= -1 and c= -6

plug in all the values in the formula

Step 1:
`x= (-(-1)+-√((-1)^2-4(2)(-6)) )/(2(2))`

Step 1 is correct

(-1)^2 = -1 times -1 = +1 (negative times negative is positive)

Instead of +1 , Harry used -1 inside the square root

So the error is in step 2

Step 2:
`x= (-(-1)+-√(1+48))/(2(2))`