+0

0
104
2

If w, x, y, and z are real numbers satisfying:

what is wx + yz?

Sep 4, 2022

#1
+53
0

https://web2.0calc.com/questions/help_50204

The answer is $$99$$ but read through the whole thing to see why

Sep 4, 2022
#2
+2540
0

Here's a way without matrixes:

Adding all 4 equations gives us $$3(w+x+y+z) = 33$$, meaning $$w+ x + y + z = 11$$.

Using this, we know $$w = -1$$$$x = -8$$$$y = 7$$, and $$z = 13$$

So, we have $$(-1 \times -8) + (7 \times 13) = \color{brown}\boxed{99}$$

Sep 6, 2022