Question

2x la patrat -7x+5=0

Answer 1

$2 {x}^{2} - 7x + 5 = 0$

$a = 2$

$b = - 7$

$c = 5$

$\Delta = {b}^{2} - 4ac$

$\Delta = {( - 7)}^{2} - 4 \times 2 \times 5$

$\Delta = 49 - 40$

$\Delta = 9$

$x_{1,2}=\frac{-b\pm\sqrt{\Delta}}{2a}$

$x_{1,2}=\frac{-( - 7)\pm\sqrt{9}}{2 \times 2}$

$x_{1,2}=\frac{7\pm3}{4}$

$x_{1}=\frac{7 + 3}{4}$

$x_{1}=\frac{10}{4}$

$x_{1}=\frac{5}{2}$

$x_{2}=\frac{7 - 3}{4}$

$x_{2}= \frac{4}{4}$

$x_{2} = 1$

Answer 2

delta=b^2-4ac=49-40=9 
x1=(-b+Vdelta)/2a=(7+3)/4=10/4=5/2
x2=(-b-Vdelta)/2a=(7-3)/4=4/4=1