Q. Use the elimination method to solve for p and q.Equation 1−2p−3q=−4Equation 2−10p−21q=−255
Write Equations: First, let's write down the system of equations we need to solve:Equation 1: −2p−3q=−4Equation 2: −10p−21q=−(255)
Multiply Equations: To use the elimination method, we need to multiply the equations by appropriate numbers so that one of the variables will be eliminated when we add or subtract the equations from each other. Let's find a common multiple for the coefficients of p or q in both equations.
Eliminate Variable: Looking at the coefficients of p, which are −2 and −10, we can multiply the first equation by 5 to get the coefficient of p in the first equation to match the coefficient of p in the second equation in terms of absolute value.So, multiplying the first equation by 5, we get:5(−2p−3q)=5(−4)−10p−15q=−20Now we have:Equation 1 (multiplied by 5): −10p−15q=−20Equation 2: −21
Solve for q: Next, we will subtract Equation 2 from the modified Equation 1 to eliminate p: (−10p−15q)−(−10p−21q)=−20−(−(255))This simplifies to:−10p+10p−15q+21q=−20+255The p terms cancel out, and we are left with:6q=−20+255
Substitute q: Now we need to solve for q. First, let's convert −20 to a fraction with a denominator of 2 to combine it with 55/2:−20=−40/2So the equation becomes:6q=−40/2+55/2
Isolate −2p: Combining the fractions, we get:6q=(−40+55)/26q=15/2Now, to solve for q, we divide both sides by 6:q=(15/2)/6q=15/12q=5/4
Solve for p: Now that we have the value of q, we can substitute it back into one of the original equations to solve for p. Let's use Equation 1:−2p−3(45)=−4−2p−415=−4First, let's convert −4 to a fraction with a denominator of 4 to combine it with −415:−4=−416So the equation becomes:−2p−415=−416
Solve for p: Now that we have the value of q, we can substitute it back into one of the original equations to solve for p. Let's use Equation 1:−2p−3(45)=−4−2p−415=−4First, let's convert −4 to a fraction with a denominator of 4 to combine it with −415:−4=−416So the equation becomes:−2p−415=−416Now we will isolate −2p:−2p=−416+415−2p=(−16+15)/4−2p=−41To solve for p, we divide both sides by −2:p=(−41)/−2p=81
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