3 years ago

4x - 7y = 3 x - 7y = 15

1 answer:

5 0

$\left \{ {{4x-7y=3} \atop {x-7y=15}} \right. \\\\
 \left \{ {{4x-7y=3} \atop {x=15+7y}} \right. \\\\ substitution\ method\\\\
4*(15+7y)-7y=3\\\\
60+28y-7y=3\\\\
60+21y=3\ \ \ \ | subtract\ \\\\
21y=-57\\\\
y=-\frac{57}{21}=-\frac{19}{7}\\\\
x=15+7*(-\frac{19}{7})=15-19=-4\\\\\ Solution :\ \left \{ {{y=-\frac{19}{7}} \atop {x=-4}} \right.$

You might be interested in

What is the value of x?<br><br><br><br> Enter your answer in the box.<br> x =

Ierofanga [76]

3x + 50 = 6x -10

add 10 to each side

3x +60 = 6x

subtract 3x from each side

60 = 3x

x = 60/3 = 20

x = 20

7 0

3 years ago

Which best explains whether or not all isosceles triangles are similar? All isosceles triangles are similar. Two angles within e

Contact [7]

By Angle-Angle simlilarity postulate :
If two angles of one triangle congruent to two angles of another, then triangles must be similar.
So, I think the answer is
<span>All isosceles triangles are not similar. The pair of congruent angles within one triangle is not necessarily congruent to the pair of congruent angles within the other triangle.

Because two base angles in </span>isosceles triangle are congruent, but it could be a lot of isosceles triangles that have different congruent base angles.
For example,
45-45-90 is an isosceles triangle, and 30-30-120 is an isosceles triangles, but they do not have 2 congruent angles.

7 0

3 years ago

What is the simplest form of the expression (–12.7y – 3.1x) + 5.9y – (4.2y + x)?

Doss [256]

Answer:

Step-by-step explanation:

$(-12.7y-3.1x)+5.9y-(4.2y+x)\\\\=-12.7y-3.1x+5.9y-4.2y-x\qquad\text{combine like terms}\\\\=(-12.7y+5.9y-4.2y)+(-3.1x-x)\\\\=-11y-4.1x$