Question

If △PQR ~ △SQT, find the value of x.

Answer 1

x = 15

Explanation:

x+13/9 = 21/x-9

x^2+4x−117=168

x^2+4x−285=0

(x−15)(x+19)=0

x=15

it cannot be a negative number so x cannot be -19

Answer 2

x = 15 or x = -19

Explanation:

ΔPQR similar to ΔSQT

SQ / QP = ST / PR

8 / 8+x+5 = x-9 / 21

8 / 13+x = x-9 / 21

(x+13)(X-9) = 168

x² + 4x - 117 = 168

x² + 4x - 285 = 0

(x - 15) (x + 19) = 0

x = 15 or x = -19