If you're enjoying the course, please spread the word on Twitter.
- Video Course
- Video Course Overview
- General GRE Info and Strategies - 7 videos (free)
- Quantitative Comparison - 7 videos (free)
- Arithmetic - 42 videos
- Powers and Roots - 43 videos
- Algebra and Equation Solving - 78 videos
- Word Problems - 54 videos
- Geometry - 48 videos
- Integer Properties - 34 videos
- Statistics - 28 videos
- Counting - 27 videos
- Probability - 25 videos
- Data Interpretation - 24 videos
- Analytical Writing - 9 videos (free)
- Sentence Equivalence - 39 videos (free)
- Text Completion - 51 videos
- Reading Comprehension - 16 videos
- Study Guide
- Philosophy
- Office Hours
- Extras
- Prices
Comment on Roots and Squares
Why do you not FOIL quantity
FOIL only applies to the
FOIL only applies to the product of binomials in the form (a+b) or (a-b). For more on this, see: https://www.greenlighttestprep.com/module/gre-algebra-and-equation-solvi...
Is it correct to say that (√a
The identity (√x)^2 = √(x^2)
The identity (√x)^2 = √(x^2) is true only for values of x such that x ≥ 0.
For negative values, however, the equation doesn't hold true. For example, let's see what happens if x = -9
We get: (√-9)^2 = √(-9^2)
Since we cannot find the square root of -9, our calculations end there.
ASIDE: In math classes where students learn about complex (aka imaginary) numbers, it is taught that (√-9) = 3i, where i is an imaginary number such that i² =-1. However, the GRE is concerned with REAL NUMBERS only. So, we cannot allow imaginary numbers (like i) into our calculations.
root(16)= +- 4. why do you
The square root NOTATION
The square root NOTATION tells us to take only the positive root.
So, √9 = 3 and √49 = 7.
Cheers,
Brent
So, is it like, when there is
And when we are told to find the roots of x^2, we take both the positive and negative roots?
I'm always confused when to take negative root and when not while finding square root.
That's perfect summary of how
That's perfect summary of how roots and squares work!