Answer:
See below.
Step-by-step explanation:
Total = 110
Let calls on third evening = x
second evening = 4x
first evening = x + 8
=> x + 4x + x + 8 = 110
=> 6x = 102
=> x = 17
First evening = x = 17 calls
Second evening = 4x = 68 calls
Third evening = x + 8 = 25 calls
Answer:
-2
Step-by-step explanation:
Add 5 to both sides to get
3x-5+5=-11+5
and simplify to get
3x = -6
x = -2
Step-by-step explanation:
3 : x = -7.5
5 : x = -10
6 : x = 12
remaining answers are correct
Answer:
(2,2)
Step-by-step explanation:
Given equations
x-3y=-4-------------------------------(1)
y=-3x+8.------------------------------(2)
Substitute 2 in 1. This means use the value of y in equation 1, to replace y
x-3(-3x+8)=-4------------------open brackets
x+9x-24=-4---------------------collect like terms
10x=-4+24
10x=20---------------------------divide by 10 both sides to get value of x
10x/10=20/10=2
x=2------------------------------use value of x in equation (2) to get value of y
y=-3x+8
y=-3(2)+8
y=-6+8=2
solutions
x=2, y=2
If you have at least as many equations as your have unknown variables, the 'system' is solvable (unless the equations are copies of eachother).
In this case, isolate one letter and plug it in the other. I'm going for the 2a in the bottom one (it doesn't matter)
2a - 4b = 12 => (divide by two and move the b's to the other side)
a = 6 + 2b. (plug this one into the top equation)
4(6+2b) + 6b = 10 => 24+8b+6b = 10 => 24 + 14b = 10 => 14b = -14 => b=-1
a = 6 + -2 = 4.
So a=4 and b=-1.
