Question

PLEASE HELP

Lateena solved the equation below. Is her solution correct? Explain why or why not.

Answer 1

it isn't correct

`x {}^(2) - 6x - 7 = 0 \\ d = 36 + 28 = 64 \\ x1 = (6 - 8)/(2) = - 1 \\ x2 = (6 + 8)/(2) = 7`

Answer 2

her solution isn't correct .

because she had done a slight mistake in her calculation.

i.e.

`√(16)=4 \:\:not \:\:16`

Explanation:

solution given:

x²-6x-7=0

making it a perfect square

we must make it on the form of (a+b)²or(a-b)²

so

x²-2*3*x+3²-3²-7=0

(x-3)²-9-7=0

(x-3)²-16=0

adding 16 on both aide

(x-3)²=16

doing square root on both side

`√((x-3)²)=√(16)`

x-3=±4

taking positive

x-3=4

adding 3 on both side

x=7

and.

taking negative

x-3=-4

adding 3 on both side

x=-4+3

x=-1

x=-1 or 7