Solve the quadratic equation x^2-6x+5=0

x2 - 6x + 5 = 0.

For simple quadratic equations such as this example we need to factorise the expression into 2 brackets: (x+a)(x+b) = 0.

To find a and b we can expand the brackets to give: x2 + (a+b)x +ab = 0.

Therefore a+b = - 6 and ab=5.

If a+b is negative and ab is positive then a and b must be negative as a negative * another negative = a positive.

We can see in this case that a = -1 and b = -5 (or the other way round).

Therefore: x2 - 6x + 5 = (x-1)(x-5) = 0.

If we take the two brackets separately then: x - 1 = 0 therefore x = 1 and x - 5 = 0 therefore x = 5.

These are the two solutions to the quadratic equation: x = 1, x = 5

WR
Answered by William R. Maths tutor

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