$\bold{ELIMINATION\ METHOD}\\\\\left\{\begin{array}{ccc}y=-x+8\\y=x+4&\TEXT{change the signs}\end{array}\right\\\underline{+\left\{\begin{array}{ccc}y=-x+8\\-y=-x-4\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad0=-2x+4\qquad\text{add}\ 2x\ \text{to both sides}\\.\qquad2x=4\qquad\text{divide both sides by 2}\\.\qquad\boxed{x=2}\\\\\text{Put it to the second equation}\\y=2+4\\\boxed{y=6}$

$\bold{SUBSTITUTION\ METHOD}\\\\\left\{\begin{array}{ccc}y=-x+8&(1)\\y=x+4&(2)\end{array}\right\\\\\text{Substitute (1) to (2)}\\\\-x+8=x+4\qquad\text{subtract 8 from both sides}\\-x=x-4\qquad\text{subtract}\ x\ \text{from both sides}\\-x-x=-4\\-2x=-4\qquad\text{divide both sides by (-2)}\\\boxed{x=2}\\\\\text{Put it to the second equation}\\y=2+4\\\boxed{y=6}$

7 0

3 years ago

Help please me with these two questions. Thank you

arlik [135]

9514 1404 393

Answer:

1. 9/20 hours doing math for 1 hour reading

2. 3 1/3 cups water to 1 cup concentrate

Step-by-step explanation:

1. You have done the math. Copy your answer into the blanks that are waiting for it.

9/20 hours on math for 1 hour reading

2. 1 2/3 ÷ 1/2 = 5/3 × 2/1 = 10/3 = 3 1/3

3 1/3 cups of water to 1 cup of juice concentrate

4 0

3 years ago