+30 1.We have a rectangle of dimensions $x - 2$ by $2x + 5$ such that its area is $8x - 6$. What is the value of $x$?
2.The equation describes the height (in feet) of a projectile launched from the surface of Mars at 51 feet per second. In how many seconds will the projectile first reach 108 feet in height?
thanks for helping btw :D
i struggle a lot
+129899 (x - 2) ( 2x + 5) = 8x - 6
2x^2 - 4x + 5x - 10 = 8x -6
2x^2 + x -10 = 8x - 6 rearrange as
2x^2 - 7x - 4 = 0
(2x + 1) ( x - 4) = 0
The second factor set = 0 is what we want
x - 4 = 0
x = 4
+129899 OK
We have that
-6t^2 + 51t = 108 divide through by -3
2t^2 - 17t = -36
2t^2 - 17t + 36 = 0 see if we can factor (you could use the Q Formula but I like to factor, if possible )
(2t - 9) ( t - 4) = 0
2t - 9 = 0 or t - 4 = 0
2t = 9 t = 4 sec
t = 9/2 sec = 4.5 sec
It first reaches 108 ft at 4 sec
