Step-by-step explanation:
Select all of the following that are quadratic equations.
x² + 3x - 5 = 0 ✓
x² - x = 3x + 7 ✓
5x - 7 = 0 X
7x² + 14x = 0 ✓
x³ - 3x² + 1 = 0 X
x - 5 = 9x + 7 X
What is quadratic equations?
Quadratic equations is a equation that has a general form like "ax² + bx = c"
For example :
x² + 3x - 5 = 0
x² + 3x = 5
x² → ax²
3x → bx
5 → c
Which expression has a value that is equivalent to 5n+13 when n=-15? n^2+13x
The area formula for a parallelogram is base*height=area. Make an equation. You know the area and the height, so plug that into the equation, and you get x*18=396. Solve for x by dividing 396 by 18 and you get 22. So, the base is 22cm.
Answer:
x= 1, y=3
Step-by-step explanation:
y= 2x +1
y= -x +4
Those two equation are in a system that means they need to be true in the same time. Just like I would say look for a car that is red and is a truck in this case we look for x and y is true that y = 2x+1 and is true that y= =x+4.
so y= 2x+1 but y is -x+4 so substitute
-x+4 = 2x +1, add x on both sides
4= 2x+x +1, subtract 1 from both sides
4-1 = 2x +x, combine like terms
3 = 3x , divide both sides by 3
x=1
if x=1 we substitute in y= -1 +4 = 3
Z=82 vertical or opposite angle theorem
15x-7 + 82=180 supplementary angles theorem
so 15x +75 =180
15x=180-75
x=105/15
x=7
