Question

Repede va rog!
1) x2 ( x la a doua) -18x+45=0

2)-x2(x la a doua)+6x-6=0

3)64x2(x la a doua) -1=0

4)3x+5y=8
2x-y=1

Answer 1

x^2 va fi la a doua:
1) delta pe patru= 36, x1= 3, x2= 15.
2) delta pe patru= 3, x1= (-3-sqrt(3))/(-1) x2=(-3+sqrt(3))/(-1)
3)64*x^2= 1 <=> x^2= 1/64 <=> x= - 1/8 x= 1/8
4) din a doua ecuatie: y= 2*x-1, substituim in prima si obtinem 3*x + 5*(2*x-1)= 8 <=> x= 9/13, deci y e 2 5/13