Answer:
21
Step-by-step explanation:
<span>7r²+9=1
</span><span>the equation is contradictory, just to prove
7r</span>² + 9 = 1
7r² + 9 -1 = 0
7r² + 8 = 0
<span>We write the equation in the form of products of
</span>
7 * (r² + 8/7) = 0
<span>the product is equal to 0 when one of the factors is zero
</span>
7≠0 ∨ (r² + 8/7) = 0
r² ≠ - 8/7
<span>any number squared is not negative.
</span><span>We proved that none of the factors is not equal to zero , so the right side of the equation is not equal to the left . The equation is contradictory</span>
Answer:
a^3-b^3
Step-by-step explanation:
(a−b)(a2+ab+b2)
=(a+−b)(a2+ab+b2)
=(a)(a2)+(a)(ab)+(a)(b2)+(−b)(a2)+(−b)(ab)+(−b)(b2)
=a3+a2b+ab2−a2b−ab2−b3
=a3−b3
Answer:
All of the expressions
Step-by-step explanation:
A rational number is one that can be written as a ratio, or a number with a terminating decimal.
All of the expressions are whole numbers, so they are all rational.
