Odpowiedź:
a) x + x + x + 7 = x + x + 13
3x + 7 = 2x + 13 | -2x
x + 7 = 13 | -7
x = 6
b) [tex]\frac{(2x +3x+4)}{2}[/tex] × 3 = 102 | ÷3
[tex]\frac{(2x +3x+4)}{2}[/tex] = 34 | ×2
5x + 4 = 68 | -4
5x = 64
x = 12[tex]\frac{4}{5}[/tex]
c) 6 × (4x)² = 96
16x² = 16
x² = 1
x = 1 ∨ x = -1, ale x > 0, więc
x = 1
d) 2x + 3x + x = 180
6x = 180
x = 30
e) 2×(3x) + 2×(3x+4) = 46
6x + 6x + 8 = 46
12x + 8 = 46
12x = 38
x = 3[tex]\frac{1}{6}[/tex]
f) [tex]\frac{9x}{2}[/tex] = 4×(x+1)
9x = 8×(x+1)
9x = 8x + 8
x = 8
