<span>42.7−<span>(<span>−12.4</span>)
</span></span><span>=<span>42.7−<span>(<span>−12.4</span>)
</span></span></span><span>=<span>42.7+12.4
</span></span><span>=<span>55.1</span></span>
#5
57.8 can be rounded to 60 because 57.8 is closer to 60 than 50 and 81 is relatively close to 80. if we had to estimate the quotient, we would have
60 ÷ 80 = 0.75
#8
2.8 can be rounded to 3 because 2.8 is closer to 3 than it is to 2 and 6 can be left alone because it will make our division easier.
3 ÷ 6 = 0.5
#11
737.5 can be rounded to 700 and 9 can be rounded to 10.
700 ÷ 10 = 100
It means without preparation, extemporaneously.
Answer:
Option D is right,.
Step-by-step explanation:
-a+4b+2c=-8 ... i
3a+b-4c=9 ... ii
b=-1 ... iii
Substitute the value of b, in i and ii
-a-4+2c =-8 or -a+2c = -4
and 3a-1-4c = 9 or 3a -4c =8
Now we have two equations in two variables
-a+2c =-4 and 3a-4c =8
a = 2c+4: substitute this in the other equatin.
3(2c+4)-4c =8 Or 2c +12 =8
2c =-4 or c = -2
Substitute in -a+2c =12
-a-2 = -4
a = -2+4 =2
a=2, b=-1 and c =-1 is the solution.
28 miles
increasing by 40% = original + increase = 100 + 40 = 140% = 1.4
multiplying 20 by 1.4 gives total he will run
miles run = 1.4 × 20 = 28
