area of a triangle = 1/2 base x height
56.4 = 1/2 x 12 x height
56.4 = 6 x height
height = 56.4 /6 = 9.4cm
I would say c or d. but since its multiple choice, its ok to guess sometimes.
2x² + 3x -8 = 0
a = 2 , b = 3 , c = -8
So..
D = b²-4ac = 9 + 64 = 73
for bigger solution , use x = -b + √D / 2a
For smaller solution, use x = -b - √D / 2a
So
= -3 + √73 / 2. 2
= 1/4 (√73 -3)
Hopefully helpfull.. ^_^
So you always want y in front of the equation no matter what so you have x +2y=5 so you take the x and you subtract it to both side making it 2y= 5-x so then you just have to take the 2 to both side so you have to divide it and you will get y= 5/2-x/2 so then to graph it you start with the b which is -x/2 so you go down -1 and over 2 and place your dot adn then go up 5 over 2 and then place you dot and connect them together
<ABC + <ABC = 180
3x- 9 + 7x - 1 = 180
10x - 10 = 180
10x = 190
x = 19
<ABC = 3x- 9 = 3(19) - 9 = 48
