20. Calcule o valor numérico das expressões: a) x – y (para x =5 e y = -4) b) 3x + a (para x =2 e a=6) c) 2x + m ( para x = -1 e m = -3) d) m – 2 a ( para m =3 e a = -5) e) x + y ( para x = ½ e y = -1/5) f) a –b ( para a =3 e b = -1/2)

$450 is the answer.

step-by-step explanation:

30% of 450 = 135

450-135=315

$15 each

step-by-step explanation:

$45/3 children= $15 each

an

y = 6x -3y -12

y +3y +12 = 6x

=> . x = { 2y / 3 +2 } this is equation of line in terms of x

=> . if line meets the x-axis the co-ordinates of meeting point would be ( x , 0 )

=> . x = 2 ( 0 ) / 3 + 2

=> . x = 2

so, the point is ( 2 , 0 )

the answer is 40.

proof: