7y +5-y+8= 31
7y-y= 31-5-8
6y= 31-13
6y= 18
y= 18/6
y= 3
5(3-2a)= 55
15-10a=55
-10a=55-15
-10a=40
a= 40/-10
a= -4
27-3 (X-3)
27-3X-9
-3X= -27-9
-3X= -18
X= -18/3
X= -6
16X + 2(7X + 8) -9 = 67
16X+14X+16-9=67
16X+14X= 67 - 16 + 9
30X= 60
X= 60/30
X= 2
6 ( 4a + 2 ) + 7 ( - 5a + 3 ) = 66
24a + 12 - 35a + 21 = 66
24a - 35a = 66 - 21 - 12
-11a = 33
a = 33/-11
a = -33
12 + ( 3 x + 6 ) x ( - 7 ) - 5 = 70
12+3x+6-7x-5 = 70
3x-7x = 70+5-6-12
-4x = 75-18
-4x = 57
x = 57/-4
( 7 x - 8 ) x 2 = 6 ( 3 x - 4 )
14x²-16x = 18x-24
14x² = 18x+16x-24
-14x²+34x-24
Δ = b² -4.a.c
Δ = (-34)² -4*(-14)*(-24)
Δ = 1156 - 1344
Δ = -188
Não há valor de raiz quadrada de numero negativo.
