Question

1)2(x)la2+4(x-1)-x la2. 2)(7-radical din 3)la2. 3)5pe 8 inmultit cu(-2)+2,5. 4)2(2x-1)-3(x-5)=5x. 5)12a-6a+38a.

Answer 1

1)2(x)²+4(x-1)-x²=
x²+4x-4=0
Δ=16-16=0
x₁=x₂=-4/2=-2
S={-2}

2)(7-√3)²=7²-2·7·√3+√3²=49-14√3+3=52-14√3

3)5/8·(-2)+2,5=
-5/4+25/10=
-5/4+5/2=
(-5+5·2)/4=
(-5+10)/4=5/4=1,25

4)2(2x-1)-3(x-5)=5x
4x-2-3x+15=5x
x+13=5x
x-5x=-13
-4x=-13    inmultim -1
4x=13
x=13/4
x=3,25

5)12a-6a+38a=6a+38a=44a