If rt = 6 and rs = 9, then rx =
a - sqrt(54)
b - 13.5
c - 7.2
d - 4

Option D RX=4 units

Step-by-step explanation:

we know that

In the right triangle RTS

The cosine of angle TRS is equal to

cos(TRS)=RT/RS

substitute

cos(TRS)=6/9 > equation A

In the right triangle RTX

The cosine of angle TRX is equal to

cos(TRX)=RX/RT

substitute

cos(TRX)=RX/6 > equation B

∠TRS=∠TRX > is the same angle

Match equation A and equation B

6/9=RX/6

RX=6*6/9=4 units

25% is the answer

(5x-1)^2= (5x)^2-2(5x)×1+(1)^2=25x^2-10x+1