Question

Equação de 2º grau
X2-4x-21=0
X2+13x40=0
X2-10x+9=0
X2-4x-12=0x2+8x+16=0
X2-14x+49=0
X2+10x+25=0
X2-2x+11=0
X2-5x+7=0
X2+3x+15=0

Answer 1

$x2 - 4x - 21 = 0 \\ x = - \frac{21}{2}$