$\left\{\begin{array}{ccc}2x+7y=1\\2x-4y=12&\text{change the signs}\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}2x+7y=1\\-2x+4y=-12\end{array}\right}\qquad\text{add both sides of equations}\\.\qquad\qquad11y=-11\qquad\text{divide both sides by 11}\\.\qquad\qquad \boxed{y=-1}\\\\\text{Put the value of y to the first equation:}\\\\2x+7(-1)=1\\2x-7=1\qquad\text{add 7 to both sides}\\2x=8\qquad\text{divide both sides by 2}\\\boxed{x=4}\\\\Answer:\ \boxed{x=4\ and\ y=-1\to(4,\ -1)}$

3 0

3 years ago

Factor y=x Squared-8x

Minchanka [31]

X²-8x
factor out x
x(x-8)
y=x(x-8)

6 0

2 years ago

Use the diagram of the right triangle above and round your answer to the nearest hundredth. If m <br> a. 17.32 m<br> b. 6.93 m<b

zepelin [54]

In ΔABC,
tanA = a/b
∴ a = b×tanA = 12×1/√3 = 6.928 ~ 6.93 m

7 0

2 years ago