Zusammenfassung der Ressource
Finding the roots of quadratic equations
- x(x-4) = 0
- x=0
- x-4=0 which means x=4
- OR
- 3x^2 - 7 = 0
- Manipulate the equation so x^2 = 7/3
- therefore x= +/- sq root 7/3
- x^2-10x+21=0
- cross method if possible
- (x-7)(x-3)=0
- x-7=0 ...x=7
- OR
- x-3=0 ...x=3
- When all else fails, use the quadratic equation
- Remember the coefficients are substituted NOT the terms
- Don't be lazy ... Formula line, Substitution line, then start to work it out
- Completing the square
- halve the x term & square it
- add it to both sides of the eqation
- then it becomes something like the method in the centre top
- manipulate the equation so coeffient of x^2 is +1