You can put this solution on YOUR website! solve 3xto the second power -5x=8
3x^2-5x-8=0
Use the AC Method to factor:
3x^2-8x+3x-8=0
x(3x-8)+(3x-8)=0
(3x-8)(x+1)=0
Set each factor equal to 0 an solve for x:
x=8/3 or x=-1
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Cheers,
Stan H.
You can put this solution on YOUR website! Solve for x: First, subtract 8 from both sides of the equation. Now factor this trinomial. Apply the zero product principle. and/or Add 8 to both sides. Divide both sides by 3. or This is one of the roots. Subtract 1 from both sides. This is the other root.
how do you solve 3x2 - 5x = 8?
3x² - 5x = 8
This is a quadratic equation.
1. Get zero on the right by adding -8 to both sides
3x² - 5x - 8 = 0
2. Ignore the signs and multiply the 3 by the 8, getting 24
Think of two whole numbers whose product in 15 and whose
DIFFERENCE is 5. (DIFFERENCE because of the sign before the
8 is - . If it had been + I would have said "SUM")
A little thinking gives us 8 and 3, because
8×3 = 24 and 8-3 = 5
Rewrite the 5 as (8-3)
3x² - (8-3)x - 8 = 0
Remove the parentheses
3x² - 8x + 3x - 5 = 0
Factor x out of the first two terms
x(3x - 8) + 3x - 5 = 0
Factor 1 out of the last two terms:
(Note: if you can't factor anything else
out of one of the pair of terms, factor
out 1 or -1.)
x(3x - 8) + 1(3x - 8) = 0
Now I'll do some coloring to help
you see what I'm doing:
x(3x - 8) + 1(3x - 8) = 0
Now factor out the red (3x - 8),
putting the blue x and the blue + 1 inside parentheses
(3x - 8)(x + 1) = 0
Set each factor = 0 and solve for x
3x - 8 = 0 x + 1 = 0
3x = 8 x = -1
x = 8/3
Edwin
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