(2x * 34) / 40
= 68x / 40
= 1.7x
Answer:
- 40
Step-by-step explanation:
When a = 4, and x = -4:
Evaluating algebraic expressions simply involve substituting the given values for <em>a</em> and<em> x</em> into the expression, -9a + x.
Hence, -9a + x = -9(4) + (-4) = -36 - 4 = -40
Therefore, the correct answer is -40.
let's do so using substitution
![\bf \begin{cases} -3x-4y=-14\\ 9x+2y=22 \end{cases} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{solving for "y" in the 1st equation}~\hfill }{-3x-4y=-14\implies -3x+14-4y=0} \\\\\\ -3x+14=4y\implies \cfrac{14-3x}{4}=\boxed{y} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{substituting "y" in the 2nd equation}}{9x+2\left( \boxed{\cfrac{14-3x}{4}} \right)=22}\implies 9x+\cfrac{14-3x}{2}=22](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Bcases%7D%20-3x-4y%3D-14%5C%5C%209x%2B2y%3D22%20%5Cend%7Bcases%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Cstackrel%7B%5Ctextit%7Bsolving%20for%20%22y%22%20in%20the%201st%20equation%7D~%5Chfill%20%7D%7B-3x-4y%3D-14%5Cimplies%20-3x%2B14-4y%3D0%7D%20%5C%5C%5C%5C%5C%5C%20-3x%2B14%3D4y%5Cimplies%20%5Ccfrac%7B14-3x%7D%7B4%7D%3D%5Cboxed%7By%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Cstackrel%7B%5Ctextit%7Bsubstituting%20%22y%22%20in%20the%202nd%20equation%7D%7D%7B9x%2B2%5Cleft%28%20%5Cboxed%7B%5Ccfrac%7B14-3x%7D%7B4%7D%7D%20%5Cright%29%3D22%7D%5Cimplies%209x%2B%5Ccfrac%7B14-3x%7D%7B2%7D%3D22)
![\bf \stackrel{\textit{multiplying both sides by }\stackrel{LCD}{2}}{2\left( 9x+\cfrac{14-3x}{2}\right)=2(22)}\implies 18x+(14-3x)=44\implies 15x+14=44 \\\\\\ 15x = 30\implies x = \cfrac{30}{15}\implies \blacktriangleright x = 2\blacktriangleleft \\\\\\ \stackrel{\textit{since we know that }}{\cfrac{14-3x}{4}=y}\implies \cfrac{14-3(2)}{4}=y\implies \cfrac{14-6}{4}=y\implies \blacktriangleright 2 = y \blacktriangleleft \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill (2,2)~\hfill](https://tex.z-dn.net/?f=%5Cbf%20%5Cstackrel%7B%5Ctextit%7Bmultiplying%20both%20sides%20by%20%7D%5Cstackrel%7BLCD%7D%7B2%7D%7D%7B2%5Cleft%28%209x%2B%5Ccfrac%7B14-3x%7D%7B2%7D%5Cright%29%3D2%2822%29%7D%5Cimplies%2018x%2B%2814-3x%29%3D44%5Cimplies%2015x%2B14%3D44%20%5C%5C%5C%5C%5C%5C%2015x%20%3D%2030%5Cimplies%20x%20%3D%20%5Ccfrac%7B30%7D%7B15%7D%5Cimplies%20%5Cblacktriangleright%20x%20%3D%202%5Cblacktriangleleft%20%5C%5C%5C%5C%5C%5C%20%5Cstackrel%7B%5Ctextit%7Bsince%20we%20know%20that%20%7D%7D%7B%5Ccfrac%7B14-3x%7D%7B4%7D%3Dy%7D%5Cimplies%20%5Ccfrac%7B14-3%282%29%7D%7B4%7D%3Dy%5Cimplies%20%5Ccfrac%7B14-6%7D%7B4%7D%3Dy%5Cimplies%20%5Cblacktriangleright%202%20%3D%20y%20%5Cblacktriangleleft%20%5C%5C%5C%5C%5B-0.35em%5D%20%5Crule%7B34em%7D%7B0.25pt%7D%5C%5C%5C%5C%20~%5Chfill%20%282%2C2%29~%5Chfill)
2 miles = 3520 yards (Americans wtf)
200 yards for 1 group = 5 minutes
400 yards for 2 groups = 5 minutes
1 minutes for 2 group = 80 yards
3520 yards for 2 groups = (3520:80 or 3520:400*5) minutes
So the answer is 44 minutes.
