<span><span>ab:ac=3:5
bd:cd=7:2
if cd is 5 cm then cd=2:5 then ab=3:x
2:5=3:x
15=2x
x=15/2
x=7.5 cm</span><span>
Happy studying! ^_^</span></span>
The answer is 81.75. 54 1/2 divided by 2/3
x= -15/4 => x= -3 3/4 or x= -3.75
Simultaneous equation refer to a pair of equations that are solved at the same time.
<h3>What is a simultaneous equation?</h3>
A simultaneous equation refer to a pair of equations that are solved at the same time.
For problem 1;
x = 4 - y ------ (1)
y^2 = 3x + 19 ----- (2)
Substitute (1) into (2)
y^2 = 3(4 - y) + 19
y^2 = 12 - 3y + 19
y^2 +3y - 31 =0
y = 4.27 or -7.27
x = 4 - 4.27 = 0.27
or
x = 4 - (-7.27) = 11.27
For the second problem;
x = 7 - y
y^2 = 5x - 15
Substitute (1) into (2)
y^2 = 5(7 - y) - 15
y^2 =35 -5y -15
y^2 + 5y - 20 = 0
y =2.62 or -7.62
x = 7 - 2.62 = 4.38
OR
x= 7 - (-7.62) = 14.62
Learn more about simultaneous equation:brainly.com/question/16763389
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