The distributive property: a(b + c) = ab + ac
(-7c + 8d)0.6 = (-7c)(0.6) + (8d)(0.6) = -4.2c + 4.8d
8 days because 4/5 = 8/10 and he is using 1/10 a day.
Answer:
−
1
2
+
Step-by-step explanation:
Answer:
Car 1 : 40 miles per gallon
Car 2: 25 miles per gallon
Step-by-step explanation:
family has two cars. During one particular week, the first car consumed 15 gallons of gas. The second car consumed 25 gallons of gas. The two cars Drove a combined total of 1475 miles and the sum of their fuel efficiency was 65 miles per gallon. What were the fuel efficiency of each of the cars that week
Given that :
Fuel efficiency , car 1 = x
Fuel efficiency , car 2 = y
x + y = 65 - - (1)
15x + 35y = 1475 - - - (2)
x = 65 - y
15(65-y) + 35y
975 - 15y + 35y = 1475
20y = 14875 - 975
20y = 500
y = 25
Put y = 25 in (1)
x + y = 65
x + 25 = 65
x = 65 - 25
x = 40
This is a system of equations. You can solve it by substitution or elimination. I'm going to use substitution x - 2y = -4.5; add 2y to each side x - 2y + 2y = -4.5 + 2y; simplify x = 2y - 4.5 2(2y - 4.5) + 3y = 12 4y - 9 + 3y = 12 7y - 9 = 12 7y - 9 + 9 = 12 + 9 7y = 21 y = 3 <--------first answer x - 2y = -4.5 x - 2(3) = -4.5 x - 6 = -4.5 x -6 + 6 = -4.5 + 6 x = 1.5 <--------second answer Check: 2(1.5) + 3(3) = 12? 3 + 9 = 12? 12 = 12; It checks 1.5 - 2(3) = -4.5? 1.5 - 6 = -4.5? -4.5 = -4.5; It checks x = 1.5 and y = 3 <-----------Final Answer
