Question

Using a trial and improvement method, find x correct to 1 decimal place.
3x² - x = 30

Answer 1

Here’s the answer to your question x = 3.3, -3

Answer 2

x = 10/3

x = -3

Explanation:

3x² - x = 30

3x² - x - 30 = 0

multiply 3 and -30 which =

-90

what are 2 numbers that when multiplied make

-90

and that when added make

-1

(-1 is the number in -x in the equation)

they are the numbers 9 and 10

namely -10 and +9

3(x-10/3)(x+9/3)=0

divide both sides by 3

(x-10/3)(x+9/3)=0

then split factors being multiplied

(x-10/3)=0

(x+9/3)=0

x = 10/3

x = - 9/3 = -3