The answer is 2 first you add then multiple
To solve this system by substitution, we must substitute in the value we are given for x in terms of y (the first equation) into the second equation. This is modeled below:
x = -8y - 15
2x + 5y = -8
2 (-8y - 15) + 5y = -8
Now, we should solve this new equation for y. To begin, we should use the distributive property to get rid of the parentheses on the left side of the equation and begin the simplification process.
-16y - 30 + 5y = -8
Next, we can combine like terms on the left side of the equation by adding together the two terms that both contain the variable y.
-11y - 30 = -8
Next, we should add 30 to both sides in order to move all of the constant (number) terms to the left side of the equation.
-11y = 22
After that, we should divide both sides of the equation by -11 in order to get the variable y alone.
y = -2
Now, we can substitute our value for y back into one of our original equations (it doesn't matter which one you choose; they will yield the same answer).
x = -8y - 15
x = -8(-2) - 15
To simplify, we should following the order of operations outlined by PEMDAS and compute the multiplication and then the subtraction.
x = 16 - 15
x = 1
Therefore, the answer to the system is x = 1 and y = -2, or (1,-2) when written as an ordered pair.
Hope this helps!
Answer:
x = 200
Step-by-step explanation:
Given
x - 
y = 30 ← substitute y = 15 into the equation
x - × 15 = 30 , that is
x - 10 = 30 ( add 10 to both sides )
x = 40 ( multiply both sides by 5 to clear the fraction )
x = 200
Answer:
Step-by-step explanation:
Okay so we know that line on the triangle DEF that's parallel to the line BC is EF. This because they have the same slope and we can prove that while solving for slope-intercept form.
First we figure out our points for both the lines:
BC: 
EF: 
Now that we have our points we can use the slope formula to prove these two line have the same slope and are therefore parallel to eachother:
= Slope Formula
BC = 
EF = 
So now we proved that both of these lines have a slope of -1. Then we can use the slope intercept formula and one of the points from the line EF to find the y-intercept of the of line EF:
Let's use point = 
We used the formula and found that the y-intercept was 
, so now we plug in all of our answers:
This is the complete answer but if you wanted to simplify it more you could write it as 
, cause as long as you make the x negative in the equation it will always be as if you multiplied it by -1.
15+5•y/2
15+5•4 / 2
15+20 / 2
15+10
=25
