Question

a) Stiind ca x + y + 19 = 33, determinati 3y +27 +3x; b) Stiind ca 5x + 18 + 20y = 43, determinati 15x +38 + 60y;

Answer 1

a) 3y +27 +3x = 3(x + y + 9)
Stim ca x + y + 19 = 33 => x + y + 9 = 23 (explicatie: scadem 10)
=> 3y +27 +3x = 3(x + y + 9) = 3 * 23 = 69

b) 15x + 38 + 60y = 3(5x + 20y) + 38
Stim ca 5x + 18 + 20y = 43 => 5x + 20y = 25
=> 15x + 38 + 60y = 3(5x + 20y) + 38 = 3 * 25 + 38 = 75 + 38 = 113

Answer 2

a)x+y+19=33 3x+3y+27=? 3(x+y+9)=3(x+y+19-10) x+y+9=33-10=23 3x23=69 b)5x+20y+18=43 15x+60y+38=? 3(5x+20y+18)=15x+60y+54 15x+60y+38=15x+60y+54-16=25x3+38=75+38=113