Answer:
Step-by-step explanation:
Given
Points (-1,7) and (1,3)
Formula
m = (y2 = y1) / (x2 - x1)
y2 = 7
y1 = 3
x2 = - 1
x1 = 1
Solution
m = (7 - 3) / (-1 - 1)
m = 4 / - 2
m = - 2
Now use either one of the points to get b in y = mx + b
x = 1
y = 3
m = - 2
y = mx + b
3 = -2 (1) + b
3 = -2 + b
b = 3 + 2
b = 5
Equation: y = - 2x + 5
Second question.
y = -2 + 1
Think money. You have a dollar in your pocket, but you owe your mom 2 dollars. Where are you.
y = -2 + 1
y = - 1
Answer:
Step-by-step explanation:
Answer:
7.5 L of 10% solution and 22.5 L of 30% solution
Step-by-step explanation:
Volume of 10% solution plus volume of 30% solution = total volume of 25% volume.
x + y = 30
Acid in 10% solution plus acid in 30% solution = total acid in 25% solution.
0.10 x + 0.30 y = 30 × 0.25
0.10 x + 0.30 y = 7.5
Solve the system of equations, using either substitution or elimination. I'll use substitution:
x = 30 − y
0.10 (30 − y) + 0.30 y = 7.5
3 − 0.10 y + 0.30 y = 7.5
0.20 y = 4.5
y = 22.5
x = 30 − y
x = 7.5
Sarah needs 7.5 L of 10% solution and 22.5 L of 30% solution.
