Answer:
Let the speed of the train be x km/h.
Case 1:
Distance = 288 km
Speed = x km/h
Time = Distance/Speed
= 288/x h
Case 2:
Distance = 288 km
Speed = (x+4) km/h
Time = 288/x + 4 h
Since 288/x > 288/x + 4
288/x - 288/x+4 = 1
288[1/x - 1/x+4 ] = 1
[ x + 4 - x / x(x + 4) ] = 1/288
[4 / x^2 + 4x ] = 1/288
x^2 + 4x = 1152
x^2 + 4x - 1152 = 0
x^2 + 36x - 32x - 1152 = 0
x(x + 36) - 32(x + 36) = 0
(x + 36)(x - 32) = 0
x + 36 = 0 , x - 32 = 0
x = -36 , x = 32
x = -36 , rejected since speed cannot be negative.
Therefore , speed of the train = 32 km/h
Answer: -270
Step-by-step explanation:
First, simplify the exponent
Then, distribute
Then, subtract(add a negative)
Hope it helps <3 :)
57 - 4t > = 13.....subtract 57 from both sides
-4t > = 13 - 57
-4t > = - 44 ...divide both sides by -4, and change the inequality sign
t < = -44 / -4
t < = 11
u solve inequalities much like u do equations except for one very important rule. In an inequality, if u divide/multiply by a negative number, u have to change the inequality sign.
Answer:
expand (a + 7) * 2: 2a + 14
Step-by-step explanation:
(a + 7) * 2
= 2 ( a + 7)
apply the distributive law: a(b + c) = ab + ac
a = 2, b = a, c = 7
= 2a + 2 * 7
multiply the numbers: 2 * 7 = 14
= 2a + 14
