Question

How do you solve `3x²=15x`?

Answer 1

`x=0 or x=5`

Explanation:

`3x^2=15x`

`3x^2-15x=0` subtract `15x` from both sides

`3x(x-5)=0` factorise

`3x=0 or x-5=0` solve each linear equation

`therefore x=0 or x=5`

Answer 2

`x=0" or "x=5`

Explanation:

`"express the equation in "color(blue)"standard form"`

`•color(white)(x)ax^2+bx+c=0;a!=0`

`rArr3x^2-15x=0`

`"take out a "color(blue)"common factor "3x`

`rArr3x(x-5)=0`

`"equate each factor to zero and solve for x"`

`3x=0rArrx=0`

`x=5=0rArrx=5`