Answer:
B
Step-by-step explanation:
you can use foil and the graph,
because you can see (in the graph) that the lines intersect at 1 and 4.
just use foil to help figure out which matches the slope.
something else (the normal way) is find which 2 numbers equal to the last coefficient, in this case it can be
-2 and -2, 2 and 2, 4 and 1 or -4 and -1, multiply them and if they make up the last coefficient, and added it equals the second coefficient it is correct.
Let
x ------> number of switch type A
y -----> number of switch type B
so
Remember that
1 hour=60 min
32 hours=32*60=1,920 minutes
4x+5y=1,920 -------> equation 1
3x+5y=1,740 ------> equation 2
Solve the system of equations
Solve by graphing
using a graphing tool
see the attached figure
Solution is
x=180
y=240
therefore
<h2>the number of switch type A was 180</h2><h2>the number of switch type B was 240</h2>
7% of 1,000 is 70.
280/70 = 4
It will take 4 years.
The answer is “like” terms.
You add common terms together to get variables by themselves.