(5^2 x 3^2)/15^2 = (5x3/15)^2=1
X²-8x-84 = 0
a =1; b=-8; c=-84
D = b²-4ac
D = (-8)² - 4 · 1 · (-84) = 64 + 336 = 400 (√400=20)
x1 = -b+√D/2a ⇒ -(-8)+20/2 = 28/2 = 14.
x2 = -b-√D/2a ⇒ -(-8) -20/2 = -12/2 = -6.
<span>-1,6x + 0,2y + 2,6x - 0,1 - 3,2y
-1,6*1/2+0,2*(-2/3)+2,6*1/2-0,1-3,2(-2/3)=-3,2+(-1)+5,2-0,1+3(13/15)=4(23/30)</span>