Answer:
Step-by-step explanation:
12 .x=3 y= -3
-x+2(y-1)
=-3+2(-3-1) = -3 -6 -2 = -9 -2 = -11
13.a=3
-5(a^2) -a + 5
=-5(3^2) -3 + 5 = -5(9) +2 = -45 +2 =-43
14. a = -2 b=4
-4a +3(2b-1)
= -4(-2) +3( 2(4)-1 ) =8 +3(8-1) = 8 +3(7) = 8 +21 =29
15. x = -2
3x^2 - 4x +1 =3(-2^2) -4(-2) +1 = 3(4) -4(-2) + 1 = 12 +8 +1 =20 +1 =21
