(√(7) + 1)^2 - 2 √(7)

(7+2×√7×1+1)-2√7= 8+2√7-2√7=8

(√(7) + 1)^2 - 2 √(7)  = (√7+1)^2 - 2√7 = 7 + 2√7 + 1 - 2√7 = 7 + 1 = 8.

1,5(х+-0,5х)=0,5(10-2х)

1,5х+1,5*4-7+0,5х=0,5*10-0,5*2х

1,5х+(-1)+0,5х=5-х

1,5х+0,5х+х=5+1

3х=6 (делим на 3)

х=2