I NEED HELP!!! I DONT KNOW WHAT TO DO!
2 answers:
Answer:
C
Step-by-step explanation:
the equation of a line in slope-intercept form is
y = mx + c ( m is the slope and c the y-intercept )
to calculate m use the gradient formula
m = ( y₂ - y₁ ) / ( x₂ - x₁ )
with (x₁, y₁ ( = (2, 3) and (x₂, y₂ ) = (4, - 7)
m = =
= - 5
y = - 5x + c ← is the partial equation
to find c substitute either of the 2 points into the partial equation
using (2, 3 ), then
3 = - 10 + c ⇒ c = 3 + 10 = 13
y = - 5x + 13 ← equation in slope-intercept form (1)
Add 5x to both sides
5x + y = 13 ← equation in standard form (2)
We can also express the equation in point- slope form
y - b = m(x - a )
where (a, b ) is a point on the line → using (4, - 7), then
y + 7 = - 5(x - 4 ) ← equation in point- slope form (3)
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Answer:
20 gallons of the 40% solution, 60 gallons of the 80% solution
Step-by-step explanation:
Let x = the gallons of the 40% solution, and y = the gallons of a 80% solution. The first thing we want to do here is to convert each percentage into decimal form - including the 70% solution mixture.
40% = 0.40,
80% = 0.80, respectively 70% = 0.70
As you can tell, 0.40 is associated with x gallons, 0.80 is associated with y gallons, and the mixture contains 0.70 80 solution, as 0.70 is associated with 80. Therefore we can formulate the following expression,
0.40x + 0.80y = 0.70 80
At the same time x + y = 80, as the solution ( mixture ) is present with 80 gallons. Isolating x, x = 80 - y. Let us plug that into our expression, solving for y, following by x gallons.
( Multiply either side by 10 )
( Expand )
( Substitute to solve for x )
As you can see there are 20 gallons of the 40% solution, and 60 gallons of the 80% solution.