Here is one way to solve for x.
Step 1) 2x^2-7=9
Step 2) 2x^2-7+7=9+7
Step 3) 2x^2=16
Step 4) (2x^2)/2=16/2
Step 5) x^2=8
Step 6) sqrt(x^2)=sqrt(8)
Step 7) |x|=sqrt(8)
Step 8) x=sqrt(8) or x=-sqrt(8)
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Below are explanations/reasons to each of the steps above.
Step 1) Original equation
Step 2) Add 7 to both sides
Step 3) Combine like terms
Step 4) Divide both sides by 2
Step 5) Simplify
Step 6) Apply the square root to both sides. The notation "sqrt" is shorthand for "square root"
Step 7) Use the rule that sqrt(x^2) = |x| for all real numbers x
Step 8) Use the rule that if |x| = k then x = k or x = -k for some fixed number k.
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The two solutions are
x = sqrt(8) or x = -sqrt(8)
15%
amount error is guess subtract actual amount 198-172 = 26
26/172 = 0.15
0.15 x100 = 15%
Answer:
40 5x4 20 20x2 40
Step-by-step explanation:
Answer:
-3x² +6x -1 = 0
Step-by-step explanation:
x2 - 2x + = 4(x2-2x +1)-3
x² - 2x = 4x²-8x +4 - 3
x²-4x²-2x+8x = 4-3
-3x² +6x = 1
-3x² +6x -1 = 0
