Question

Упростите и вычислите при х= -3
1) 2-(х-1)(х+1)
2) 5-(2+х)(2-х)

Answer 1

а) 2-(х-1)(х+1)= 2-($x^{2}$-1) = 2-$x^{2}$+1 = 3-$x^{2}$
3-(-3)²=3-9=-6

б) 5-(2+х)(2-х)=5-(4-х²)=5-4+х²=1+х²
1+(-3)²=1+9=10