Question

Rezolvati exercitiile:
a.(x-1)²=49
b.(2x+1)²=81
c.(3x-1)²=121
d.3(x-3)²=48
e.5(x+2)²=45
f.7(2x-1)²=175

Answer 1

a.(x-1)²=49=7^2
x-1=7 => x=8
x-1=-7 => x=-6

b.(2x+1)²=81=9^2
2x+1=9 => x=4
2x+1=-9 => x=-5

c.(3x-1)²=121=11^2
3x-1=11 => x=4
3x-1=-11 => x=-10/3

d.3(x-3)²=48
3x^2−18x+27=48
3x^2−18x−21=0
3(x+1)(x−7)=0
x= -1 sau x=7

e.5(x+2)²=45
5x^2+20x+20=45
5x^2+20x−25=0
5(x−1)(x+5)=0
x=1 sau x=-5

f.7(2x-1)²=175
28x^2−28x+7=175
28x^2−28x−168=0
28(x+2)(x−3)=0
x=-2 sau x=3