Pls help this stuff is so hard to understand

Using elimination, what is -4x+2y=-12 4x+8y=-24

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.

What percent of $1.00 are a nickel and a dime?