Please help 50 points! ​

d=10

Solution given:

squaring both side

25+3x=(d+2x)²

when x=-3

25+3*-3=(d+2*-3)²

25-9=(d-6)²

16=(d-6)²

4=d-6

d=4-6

d=10

what i would say the best answer is a. 40.5

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)