the length of a rectangle is 7 cm more than its width and the area is 30 cm find the length, width and the perimeter

Step-by-step explanation:

let width=x

length=x+7

x(x+7)=30

x²+7x-30=0

x²+10x-3x-30=0

x(x+10)-3(x+10)=0

(x+10)(x-3)=0

either x=-10 (rejected being negative)

or x=3

width=3 cm

length=3+7=10 cm

Perimeter=2(10+3)=2×13=26 cm

1/2*qr*rs

step-by-step explanation:

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)