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Equation 1: 3x+y= 11, Equation 2: 2x+y=8. You want to find out what x is and what y is.In both equations there is only 1 unit of y therefore it is easiest to rearrange the first equation so that it equals...

18/(3+2)=3.63x3.6=10.8 2x3.6=7.210.8x2.8=30.247.2x3.5=25.230.24+25.2=55.44

Re-arrange y-2x-4=0 to y=2x+4Substitute y=2x+4 into 4x^2+y^2+20x=0 to get 4x^2+(2x+4)^2+20x=0Expand the brackets to get 4x^2+(4x^2+16x+16)+20x=0Simplify to get 8x^2+36x+16=0Divide by 4 to get 2x^2+9x+4=0F...

expand the brackets to obtain x^2=4(x^2-6x+9)expand the brackets to obtain x^2=4x^2-24x+36rearrange to obtain 0=3x^2-24x+36factorise to obtain 0=(3x-6)(x-6)solve for x=6 or x=2

y= 2x^2 + 8x + 5 is a simple quadratic equation and can be easily differentiated. Consider it in different terms working from left to right: y converts to dy/dx. This just means ‘differentiate y with resp...