Question

Find x, if 3x − 5(y + x ) ^2 = 16 and 4x + 2(y + x )^ 2 = 30

Answer 1

Answer:

x = 7

Step-by-step explanation:

Start by solving for $(y+x)^2$ which is a common expression for both equations. Then in the first equation:

$3\,x5\,(y+x)^2=16\\3x-16=5\,(y+x)^2\\(y+x)^2=\frac{3\,x-16}{5}$

and in the second equation:

$4\,x+2\,(y+x)^2=30\\2\,(y+x)^2=30-4\,x\\(y+x)^2=15-2\,x$

Now we make the two $(y+x)^2$ expressions equal so we get:

$\frac{3\,x-16}{5} =15-2\,x\\3\,x-16=75-10\,x\\13\,x=75+16\\13\,x=91\\x=7$