Answer: (4, -9)
<u>Step-by-step explanation:</u>
Use elimination method. Manipulate one (or both) equations to eliminate one of the variables and solve for the remaining variable. <em>I will be eliminating y</em>
6x + y = 15 → 2(6x + y = 15) → 12x + 2y = 30
-7x - 2y = -10 → 1(-7x + 2y = -10) → <u> -7x - 2y = -10</u>
5x = 20
x = 4
Next, replace "x" with "4" into either equation and solve for y.
6(4) + y = 15
24 + y = 15
y = -9
<u>Check:</u>
Plug in x = 4 and y = -9 into the other equation to verify it makes a true statement.
-7x - 2y = -10
-7(4) - 2(-9) = -10
-28 - -18 = -10
-28 + 18 = -10
-10 = -10 
Answer:
x = 15
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°
Sum the 3 given angles and equate to 180, that is
3x - 10 + 6x + 5 + 4x - 10 = 180, simplify left side
13x - 15 = 180 ( add 15 to both sides )
13x = 195 ( divide both sides by 13 )
x = 15
The linear equation y = -6x + 2; -12x - 2y = -4 has no solution
<h3>Linear equation</h3>
y = -6x + 2
-12x - 2y = -4
- Substitute y = -6x + 2 into (2)
-12x - 2y = -4
-12x - 2(-6x + 2) = -4
-12x + 12x -4 = -4
-12x + 12x = - 4 + 4
0 = 0
y = -6x + 2
y - 2 = -6x
x = (y - 2) / -6
-12x - 2y = -4
-12(y- 2)/ 6 - 2y = -4
(-12y + 24) / 6 - 2y = -4
-2y + 4 - 2y = 4
0 = 0
Learn more about linear equation:
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Answer:
225/4
Step-by-step explanation:
x²– 15x – 23 = 0
To complete the square
We take to coefficient of the x term
-15
divide by 2
-15/2
Square it
225/4
Add it to each term