<em><span>а) 10x^2 - 10x + m = 0</span></em>
<em><span>>1 корень => d>=0</span></em>
<em><span>D=d^2-4ac=100-40m</span></em>
<em><span>100-40m>=0</span></em>
<em><span>m<=2,5</span></em>
<em><span><span>а) kx^2 + 8x - 15 = 0</span></span></em>
<em><span><span>0 корень => d<0</span></span></em>
<em><span><span>d=64+60k</span></span></em>
<em><span><span>64+60k<0</span></span></em>
<em><span><span>k<-16:15</span></span></em>
<em><span><span><span>а) 2,5x^2 + 4x = 0</span></span></span></em>
<em><span><span><span>x(2,5x+4)=0</span></span></span></em>
<em><span><span><span>1)x=0</span></span></span></em>
<em><span><span><span>2)2,5x+4=0</span></span></span></em>
<em><span><span><span>x=-1,6</span></span></span></em>
<em><span><span><span><span>б) 6y^2 - 0,24 = 0</span></span></span></span></em>
<em><span><span><span><span>6y(y-0,4)=0</span></span></span></span></em>
<em><span><span><span><span>1)6y=0</span></span></span></span></em>
<em><span><span><span><span>y=0</span></span></span></span></em>
<em><span><span><span><span>2)y-0,4=0</span></span></span></span></em>
<em><span><span><span><span>y=0,4</span></span></span></span></em>
<em><span><span><span><span><span>в) 0,2t^2 - t - 4,8 = 0</span></span></span></span></span></em>
<em><span><span><span><span><span>t^2-5t-24=0</span></span></span></span></span></em>
<em><span><span><span><span><span>d=b^2-4ac=25-4*(-24)=121</span></span></span></span></span></em>
<em>t=-3</em>
<em>t=8</em>