Solve for x: the quantity of x plus 20 over 2 = 3x

x = 4

Step-by-step explanation:

For this problem, we simply need to convert the words into the left hand side of the equation and solve for x:

The quantity of implies a grouping

x plus 20 is the quantity

And we want the quantity over 2 all equal to 3x:

( x + 20 ) / 2  = 3x

( x + 20 )  = 6x

20 = 5x

4 = x

And now we can check to see if x is correct by plugging back into the equation:

( x + 20 ) / 2 = 3x

( (4) + 20 ) / 2 ?= 3(4)

( 24 ) / 2 ?= 12

12 == 12

Therefore, we have shown the value of x to be equal to 4.

Cheers.

x+20/2=3x.

6x=x+20.

6x-x=20.

5x=20.

x=4.

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form