Question

Doar a și b..va rog...Și vreau rezolvarea completă...

Answer 1

a) 7x²+3x–4=?

7x²+3x–4=0

a=7, b=3, c=–4

∆=b²–4ac=3²–4*7*(–4)=9+112=121

x1,2=(–b±√∆)/2a

x1=(–3+√121)/14=(11–3)/14=8/14=4/7

x2=(–3–√121)/14=(–3–11)/14=–14/14=–1

ax²+bx+c=a(x–x1)(x–x2)

7x²+3x–4=7(x–4/7)(x+1)=(7x–4)(x+1)

b)5x²–7x+2=?

5x²–7x+2=0

a=5, b=–7, c=2

∆=b²–4ac=(–7)²–4*5*2=49–40=9

x1,2=(–b±√∆)/2a

x1=(7+√9)/10=(7+3)/10=10/10=1

x2=(7–√9)/10=(7–3)/10=4/10=2/5

ax²+bx+c=a(x–x1)(x–x2)

5x²–7x+2=5(x–1)(x–2/5)=(x–1)(5x–2)