X^{2} - 3 x - 10 - ( x^{2} + x - 12) = 0 x^{2} - 3 x - 10 - x^{2} - x + 12 = 0 -4 x + 2 =0-4 x= -2<span> x = 0.5</span>
1) 10x^2-14x = 2x^2 - 5
8x^2-14x+5=0
Корни x=0.5 , x=5/4
2) x^2+8x+16 = 4x^2 +14
3x^2-8x-2=0
Корень x=-4
3)x^2-10x+25=3x^2-x+14
2x^2+9x-11=0
Корни x=11/2 =5.5, x= 1
Наверное так........./.........
10x+20=-7
10x=-7-20
10x=-27
x=-2,7
A1+a5=8⇒2a1+4d=8⇒a1+2d=4⇒a1=4-2d
a2*a4=7⇒(a1+d)(a1+3d)=7
(4-2d+d)(4-2d+3d)=7
(4-d)(4+d)=7
16-d²=7
d²=9
d1=3 не удов усл
d=-3
a1=4-2*(-3)=4+6=10
a12=a1+11d
a12=10-3*11=10-33=-23