ECUATII 1. x la a2a +3x=4 , 2. x la a2a -4x=21, 3. x la a2a +6x=27 , 4. x la a2a +2x=8 , 5. x la a2a +5x=14 , 6. 4(x+3)=(x+2) la a2a, 7. x la a2a +y la a2a -6x +2y+10=0 , 8.2x la a2a-1 , 0. 4x la a2a -4x+1VA ROG MULT CINE STIE SA LE REZOLVE MULTUMESC FURMOS .

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Răspunsuri

2014-06-08T22:53:22+03:00
1.x²+3x-4=0;Δ=9+16=25;x1= (-3+√25)/2;x1= (-3+5)/2=1;x2= (-3-√25)/2=(-3-5)/2= -4
2.x²-4x-21=0;Δ=16+84=100;x1=(4+10)/2=7;x2=(4-10)/2= -3;
3.x²+6x-27=0;Δ=36+108=144;x1=(-6+12)/2=3;x2=(-6-12)/2= -9;
4.x²+2x-8=0;Δ=4+32=36;x1=(-4+6)/2=1;x2=(-4-6)/2= -5;
5.x²+5x-14=0;Δ=25+56=81;x1=(-5+9)/2=2;x2=(-5-9)/2= -7;
6.x²+4x+4-4x-12=0;x²-8=0;Δ=32;x1=2√2 ; x2= -2√2;
7.x²+y²-6x+2y+10=0;x²-6x+9+y²+2y+1=0;(x-3)²+(y+1)²=0;x=3;y= -1;
8.2x²-1=0;(√2x+1)(√2x-1);√2x= -1⇒x= -1/√2= -√2/2;√2x=1⇒x=√2/2;
9.4x²-4x+1=0;Δ=16-16=0;x1=x2= -b/2a=4/8=1/2