А)
3x-5=0
3x = 5
x = 5/3
б)
7x-4=0
7x = 4
x = 4/7
в)
7-x = 0
-x = -7
x = 7
г)
5-x=0
-x = -5
x = 5
д)
18-10x=0
-10x = -18
x = 1,8
е)
15-7x = 0
-7x = -15
x = 15/7
ж)
x-2x+3 = 7
x = 4
з)
2x-4x-1 =2
-2x = 3
x = -1,5
и)
3x-5=x
3x-x = 5
2x = 5
x = 2,5
к)
4x-2=x
4x-x = 2
3x = 2
x = 2/3
л)
x-3 = 2x+1
x-2x = 1+3
-x = 4
x = -4
м)
3x+2 = 5x - 7
3x-5x = -7-2
-2x = -9
x = 4,5
Sin^2a+cos^2a=1
cos^2a=1-sin^2a
sin^2a=0,5
3*0,5-1=0,5
9m^2-48m+64+16m^2-64+100m=25m^2+52m
А= √22-√20=√22-√2²·5=√22-√2²·√5=√22-2√5 ≈ 0,218
В= √20-√18=2√5-3√2 ≈ 0,229
А < В
Решение:
v0t+at^2/2<40
54t+18t^2/2-40<0
9t^2+54t-40=0
t=(-27+sqrt(729+360))/9=(-27+33)/9=2/3 ч
2/3*60=40 мин