$\left\{\begin{array}{ccc}x+3y-z=2\\4x+2y+5z=1\\3x+z=12&\to z=12-3x\end{array}\right\\\\\text{substitute the value of z to the first and second equation}\\\\\left\{\begin{array}{ccc}x+3y-(12-3x)=2\\4x+2y+5(12-3x)=1\end{array}\right\\\\\left\{\begin{array}{ccc}x+3y-12+3x=2&|+12\\4x+2y+60-15x=1&|-60\end{array}\right\\\\\left\{\begin{array}{ccc}4x+3y=14&|\cdot2\\-11x+2y=-59&|\cdot(-3)\end{array}\right$

$\underline{+\left\{\begin{array}{ccc}8x+6y=28\\33x-6y=177\end{array}\right}\ \ \ \ |\text{add both sides of the equations}\\.\ \ \ \ \ \ \ 41x=205\ \ \ \ |:41\\.\ \ \ \ \ \ \ x=5\\\\\text{substitute the value of x to the first equation}\\\\4(5)+3y=14\\20+3y=14\ \ \ \ |-20\\3y=-6\ \ \ \ \ |:3\\y=-2\\\\\text{substitute the value of x to the equation:}\ z=12-3x\\\\z=12-3(5)=12-15=-3\\\\x=5,\ y=-2,\ z=-3\to(5,\ -2,\ -3)$

6 0

3 years ago

1d Round 103.459 to the nearest whole number.

d1i1m1o1n [39]

Since your trying to round 103.459 to the nearest whole number, you have to find if the tens place is a 5 or greater. If not, the whole number stays the same. In the instance, 103.459 can't be rounded up more, because 4 is not able to round it to 104. So your answer would be 103.

3 0

2 years ago

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