The equation can be rewritten with a -1−1 in front of the (10-x)(10−x) instead of just having a negative sign:
-3(3x+15)-1(10+X)=35−3(3x+15)−1(10+X)=35
First, distribute the -3−3 to the numbers in the parentheses:
-9x-45-1(10+x)=35−9x−45−1(10+x)=35
Then, distribute the -1−1 to the numbers in the parentheses:
-9x-45-10-x=35−9x−45−10−x=35
Now you need to isolate all xx terms on one side so you can eventually solve for it - to do this, add 4545 and 1010 to both sides of the equation:
-9x-45-10-x +45 +10=35 +45 +10−9x−45−10−x+45+10=35+45+10
-9x-x=35 +45 +10−9x−x=35+45+10
-10x = 90−10x=90
Divide both sides by -10−10 to get x by itself:
(-10x)/-10 = 90/(-10)−10x−10=90−10
x = -9x=−9
So, x = -9x=−9.