Question

1.已知25X的平方-144=0,且x是正数,求代数式2根号5X+13的值

Answer 1

1.

25X^2-144=0

25X^2=144

X^2=5.76

x=2.4

代入:

2倍根号5X+13

=2倍根号(12+13)

=2倍根号(25)

=2*5

=10

2.

4/3πR^3=26^3

R^3=26^3*(3π/4)

R=16.1(dm)