Answer:
the second answer is right
Step-by-step explanation:
while it is true that W=25/8, the definition itself (25/8) makes it a rational number (= a ratio of 2 integer numbers). so, in total, the first answer is therefore wrong.
X=pi, and pi is a typical example of an irrational number. so, this second answer is correct.
sqrt(10) < 3.16666666666...
so, Y=sqrt(10) and not 3.166666666..., so the third answer is already wrong there.
and consequently, Z=3.166666... and not sqrt(10), so the fourth answer is therefore also wrong.
-- Look at the two numbers.
-- Say to yourself: "Self ! 3.9 is close to 4, and 5.3 is close to 5.
So the product is going to be close to (4 x 5) = 20."
-- Then do the real multiplication.
-- On your paper or your calculator, you see the digits 2 0 6 7 .
-- From your estimate (20), you know that it can't possibly be
2.067 or 206.7 or 2,067. It must be 20.67 .
Find the vertex:
x = 10/(-2) = -5! Yeah!
