Algebra

posted by .

1. √(9y - 196) + √196 = √49

My work:

I squared all 3 roots and got

9y - 196 + 196 = 49

The - 196 + 196 cancels out and we are left with 9y = 49.
divide 49 by 9. = 49/9. I'm pretty sure this is wrong. Can you show me where I messed up?

2. √x(√9 - 4/3) = √25

I'm not quite sure where to start with this.

3. (4 - 3√2)^2

My work: Distributive property gives me 4^2 - 3^2√2^2
The √2^2 simplifies to 2, 4^2 is 16, 3^2 is 9, So we have 16-9x2 Multiply first, so 16 - 18 = -2.

Is this correct?

4. √(135*b^2*c^3*d) * √(5b^2*d

Okay, so I broke this down like this: √135 * √b^2 * √c^2 * √c * √d * √5 * √b^2 * √d

Both the √b^2's and the √c^2 simplify down to b,b, and c

so now we have b^2c√(135 * 5cd^2) Simplifies to b^2cd√(5^2 * 3^2 * 3) which simplifies to 15b^2cd√3

Is this correct? If not can you tell me where I went wrong?

Thank you!

  • Algebra -

    If a+b = c you cannot say that a^2+b^2 = c^2

    √(9y - 196) + √196 = √49
    √(9y - 196) + 14 = 7
    √(9y - 196) = -7
    But, √N is positive. So, you cannot have √(9y - 196) = -7

    √x(√9 - 4/3) = √25
    √x(3 - 4/3) = 5
    √x(5/3) = 5
    √x = 3
    x = 9

    (4 - 3√2)^2
    recall that (a-b)^2 = a^2-2ab+b^2, so we have
    16 - 24√2 + 18
    44 - 24√2

    almost right - you lost a √c
    √(135*b^2*c^3*d) * √(5b^2*d)
    √(135*5) √(b^2*b^2) √c^3 √(d*d)
    15√3 b^2 c√c d
    15b^2cd √(3c)

  • Algebra -

    I have a couple questions about # 1.
    Why can't it be a^2 + B^2 = c^2?
    I think that's what I'm taught in class. Also, if you square everything, isn't still going to come out the same? If you do something to the entire expression, it doesn't change the value, right? If your conclusion is correct, what would I put for that answer? "No solution"? "No real solution"?

    On #3. Would I do 44-24 = 20√2.. or?

  • Algebra -

    For #1: When I get √(9y - 196) = -7 can I square each side to get 9y - 196 = 49? Then I can add 196 to both sides. It cancels out on the left side and I have 9y = 245. Then I can divide both sides by 9. I would get y = 27.2. Would that be correct?

  • Algebra -

    You say that I can't use a^2 + b^2 = c^2, but that formula is called the Pythagorean theorem. I was instructed to use that formula. Am I misunderstanding what you're saying?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. HARD MATH PROBLEM (NEED HELP)

    One day a person went to a hourse racing area,instead of counting the humans and the horses he instead counted the heads and leg there where 74 heads and 196 legs yet he still knew the number of the humans and the hourses.How did he …
  2. Math- CAN SOMEONE PLEASE CHECK MY WORK?

    7x+5y=-26 x=28-6y solve using substitution okay so then 196-42y+5y=-26 then combined like terms so 196+37y=-26 37y=-222 y=-6 is this part correct?
  3. physics

    A pendulum that consists of a 2kg mass swings a maximum vertical displacement of 10 cm above its rest position. At its lowest point, the KE of the mass is equal to F. 0.196 J G. 1.96 J H. 19.6 J J. 196 J K. 1960 J
  4. Physics

    What force is needed to give a 0.25-kg arrow an acceleration of 196 m/s2?
  5. Math is this right?

    5/28 divided by 1/7 = ? 5 Do I flip the second fraction only when its division then times across?
  6. Physics

    Nitrogen boils at -196°C. What is the corresponding temperature in the Fahrenheit scale?
  7. chemistry

    Liquid hydrogen peroxide, an oxidizing agent in many rocket fuel mixtures, releases oxygen gas on decomposition. 2 H2O2(l) 2 H2O(l) + O2(g) Hrxn = -196.1 kJ How much heat is released when 529 kg H2O2 decomposes?
  8. chemistry

    Liquid hydrogen peroxide, an oxidizing agent in many rocket fuel mixtures, releases oxygen gas on decomposition. 2 H2O2(l) 2 H2O(l) + O2(g) Hrxn = -196.1 kJ How much heat is released when 529 kg H2O2 decomposes?
  9. chemistry

    Liquid hydrogen peroxide, an oxidizing agent in many rocket fuel mixtures, releases oxygen gas on decomposition. 2 H2O2(l) 2 H2O(l) + O2(g) Hrxn = -196.1 kJ How much heat is released when 529 kg H2O2 decomposes?
  10. Physical Science

    What force is needed to give a 0.25-kg arrow an acceleration of 196 m/s2?

More Similar Questions