28: x+y = 90 we substitute y with the given function 4x - 10 x + 4x - 10 = 905x -10 = 90 5x = 100= 100 ÷ 5x = 20, now you can substitute x in 4x - 10 =4(20) - 1080 - 10 = 70, which makes sense as 20º +70º = 90ºyour 2 angles are 20º and 70º 29: x + y = 90 x = 2y Same thing we did above, substitute the given variable into the given equation so, 2y + y = 90 = 3y=90, divide the 3 to both sides, y = 30, now substitue the y into your given x variable.x = 2(30)x= 60this makes sense as 60º + 30º do equal 90ºyour two angles are 60º and 30º30: x + y = 90 y = 2 (x - 15)ill do this one without explanation as you know what I am doing from the above examples. here is the work: x + 2(x-15)=90 (simplify) x+2x-30 = 903x-30=903x = 120x = 40now input to other equation2(40 - 15) = y (USE PEMDAS)2(25) = yy = 50 makes sense because 50º + 40º = 90ºyour two angles are 50º and 40º
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