Determine the value of a + b in the system of equations below.

5a + 4b = 22
7a-b= 11

We have a + b as;

2 + 3 = 5

Step-by-step explanation:

Here, we want go get the value of a and b

from the second equation, we can get an expression for b

We have this as;

7a - b = 11

Thus,

b = 7a - 11

Now, from here, we can substitute the value of b into the first equation

We have this as;

5a + 4(7a - 11) = 22

5a + 28a -44 = 22

33a = 22 + 44

33a = 66

a = 66/33

a = 2

Recall;

b = 7a - 11

substituting the value of a from above;

b = 7(2) - 11

b = 14 - 11

b = 3

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m

30 people weigh 160 pounds or more