Răspuns:
Explicație pas cu pas:
a) -4-{6-[-3+(-3)+(-5-x)-7]-9} = 1 <=> 6-[-3+(-3)+(-5-x)-7]-9 = 1+4 <=>
-[-3+(-3)+(-5-x)-7]-9 = 5-6 <=> -[-3+(-3)+(-5-x)-7] = -1 +9 <=>
-[-3-3-5-x-7] = 8 <=> 3+3+5+x+7 = 8 <=> 18+x = 8 <=> x = 8-18 =>
x = -10
b) 5·(1-2x)+1 = 4·(x+3)+8 <=> 5-10x+1 = 4x+12+8 <=> 6-10x = 4x+20 <=>
-10x-4x = 20-6 <=> -14x = 14 => x = 14:(-14) => x = -1
c) I2x-3I = 11 => 2x-3 = 11 => 2x = 11+3 <=> 2x = 14 => x = 14:2 => x = 7
-2x+3 = 11 => -2x = 11-3 <=> -2x = 8 =>x =8:(-2) => x = -4
d) 5·(-3+x) = -(4-x) + (-3·7+2x) <=> -15+5x = -4+x-21+2x <=>
5x-3x = 15-25 => 2x = -10 => x = (-10):2 => x = -5
e) I 3y+41 I = 26 => 3y+41 = 26 => 3y = 26-41 => 3y = -15 =>
y = (-15):3 => y = -5
-3y-41 = 26 => 3y = -41-26 => 3y = -67 =>
y = (-67)/3 = -67/3 ∉Z
f) z(z-4) = z(z+4) -(-24) <=> z²-4z = z²+4z+24 <=>
z²-z²-4z-4z = 24 <=> -8z = 24 => z = 24:(-8) => z = -3
