Question

POR FAVOR EU PRECISO DESSA AJUDA

a) 2x²-7x=15
b)4x²+9=12x

Answer 1

2x²-7x=15
2x²-7x-15=0
Δ=b²-4ac
Δ=(-7)² -4(2)(-15)
Δ=49+120
Δ=169
√Δ=13

x= -b +/- √Δ/2a
x=7 +/- 13/ 2(2)
x= 7 +/- 13/ 4

x'= 7+13 /4       
x'=20/4                 
x'=5  

x"= 7-13 / 4
x"= -6/4
x"= -3/2

Logo X (5, -3/2)

b)  4x² +9=12x
4x²-12x+9=0
Δ=b²-4ac
Δ=(-12)² -4(4)(9)
Δ=144-144
Δ=0

x= -b +/- √Δ/2a
x=12/2(4)
x=12/8
x= 3/2

x=x'=x"= 3/2