Răspuns :
a) 7(1-x)+21=14
7-7x+21=14
7x=28-14
7x=14
x=2
b) 1-9x+5(2x-3)≤-19
1-9x+10x-15≤-19
x≤-19+14
x≤-5
7-7x+21=14
7x=28-14
7x=14
x=2
b) 1-9x+5(2x-3)≤-19
1-9x+10x-15≤-19
x≤-19+14
x≤-5