Question

resolva as equações (U=R)

b) 49x²+28x=0

c) x²+6x-27=0

d)5x²+7x+3=0

e) 5x²-45=0

f) 6x²+18x=0

g) (x-3).(2x-1)+(x+2).(2x+1)=17

Answer 1

b) 49x²+28x=0
delta=b²-4.a.c
delta=28²-4.49.0
delta=784

c) x²+6x-27=0
 delta=b²-4.a.c
delta=6²-4.1.(-27)
delta=36+108
delta=144

d) 5x²+7x+3=0
delta=b²-4.a.c
delta=7²-4.5.3
delta=49-60
delta= -11

e) 5x²-45=0
delta=b²-4.a.c
delta=0²-4.5.(-45)
delta=900

f) 9x²+18x=0
delta=b²-4.a.c
delta=18²-4.9.0
delta=324

g) (x-3).(2x-1)+(x+2).(2x+1)=17
     2x²-x-6x+3+2x²+x+4x+2-17=0
     2x²+2x²-x-6x+x+4x+3+2-17=0
     4x²-2x-12=0
delta=b²-4.a.c
delta=(-2)²-4.4.(-12)
delta=4+192
delta=196