[tex]a) \ 7+3x = 2(4-x)\\\\L = 7+3\cdot5 = 7+15 = 22\\\\P = 2(4-5) = 2\cdot(-1) = -4\\\\L \neq P[/tex]
[tex]b) \ 4(6-x) = 2(x-3)\\\\L = 4(6-5) = 4\cdot 1 = 4\\\\P=2(5-3) = 2\cdot2 = 4\\\\\underline{L = P}[/tex]
[tex]c) \ 0,5x+20 = 4,4x\\\\L = 0,5\cdot5 = 2,5\\\\P=4,4\cdot5=22\\\\L \neq P[/tex]
[tex]d) \ 20+x = 20-[20-(20-x)]\\\\L = 20+5 = 25\\\\P =20-[20-(20-5)] = 20-[20-15] =20-5 = 15\\\\L\neq P[/tex]
Odp. Równanie b) jest spełnione przez liczbę 5.
