Answer:
Step-by-step explanation:
y = -8x - 49
y = -x
- -8x - 49 = -x
- -8x + x = 49
- -7x = 49
- x = -7
- y = - (-7) = 7
45c = 5 · 9c
10d = 5 · 2d
45c + 10d = 5 · 9c + 5 · 2d = 5(9c + 2d)
Orders are a, b, c, lets write equations to represent the problem's info:
a + b = 150
b + c = 100
a + c = 150
so we have 3 unknowns and 3 equations, so we can solve.
<span>Use the first equation:
a + b = 150
</span>a = 150 - b
and substitute in the 3rd:
<span>a + c = 150
</span>150 - b + c = 150
then
b = c
and we can substitute that in the original equation:
<span>b + c = 100
</span>2b = 100
b = 50
c = 50
and substitute in the first equation:
<span>a + b = 150
</span>a = 150 - b = 150 - 50
a = 100
then a = 100, b = c = 50
